new file mode 100644
@@ -0,0 +1,75 @@
+From 26b64ec55944b375ead223a214c5f4301329511f Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Thu, 23 Apr 2026 18:20:15 +0200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: lib/util: inline
+ string_sub2() into string_sub() the only caller
+
+This will simplify further changes.
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/26b64ec55944b375ead223a214c5f4301329511f]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 26b64ec55944b375ead223a214c5f4301329511f)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ lib/util/substitute.c | 20 ++------------------
+ 1 file changed, 2 insertions(+), 18 deletions(-)
+
+diff --git a/lib/util/substitute.c b/lib/util/substitute.c
+index b7b5588da863..26362ca77b2c 100644
+--- a/lib/util/substitute.c
++++ b/lib/util/substitute.c
+@@ -47,10 +47,9 @@
+ use of len==0 which was for no length checks to be done.
+ **/
+
+-static void string_sub2(char *s,const char *pattern, const char *insert, size_t len,
+- bool remove_unsafe_characters, bool replace_once,
+- bool allow_trailing_dollar)
++void string_sub(char *s, const char *pattern, const char *insert, size_t len)
+ {
++ bool remove_unsafe_characters = true;
+ char *p;
+ size_t ls, lp, li, i;
+
+@@ -79,13 +78,6 @@ static void string_sub2(char *s,const char *pattern, const char *insert, size_t
+ for (i=0;i<li;i++) {
+ switch (insert[i]) {
+ case '$':
+- /* allow a trailing $
+- * (as in machine accounts) */
+- if (allow_trailing_dollar && (i == li - 1 )) {
+- p[i] = insert[i];
+- break;
+- }
+- FALL_THROUGH;
+ case '`':
+ case '"':
+ case '\'':
+@@ -107,17 +99,9 @@ static void string_sub2(char *s,const char *pattern, const char *insert, size_t
+ }
+ s = p + li;
+ ls = ls + li - lp;
+-
+- if (replace_once)
+- break;
+ }
+ }
+
+-void string_sub(char *s,const char *pattern, const char *insert, size_t len)
+-{
+- string_sub2( s, pattern, insert, len, true, false, false );
+-}
+-
+ /**
+ Similar to string_sub() but allows for any character to be substituted.
+ Use with caution!
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,339 @@
+From d291377ac1ea515ac064ac00d59e1787db5671d1 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Thu, 7 May 2026 18:10:50 +0200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: lib/util: add
+ talloc_string_sub_{mixed_quoting,unsafe}() helpers
+
+This is the basic helper function for the security problems.
+
+talloc_string_sub_mixed_quoting() checks for strange quoting
+in smb.conf options.
+
+And talloc_string_sub_unsafe() tries to autodetect how the unsafe
+(client controlled value) and masked and single quote it,
+as a fallback for strange quoting a fixed fallback string
+is used and the caller should warn the admin and give
+hints how to fix the configuration.
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+Pair-Programmed-With: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/d291377ac1ea515ac064ac00d59e1787db5671d1]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit d291377ac1ea515ac064ac00d59e1787db5671d1)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ lib/util/substitute.c | 260 ++++++++++++++++++++++++++++++++++++++++++
+ lib/util/substitute.h | 17 +++
+ 2 files changed, 277 insertions(+)
+
+diff --git a/lib/util/substitute.c b/lib/util/substitute.c
+index 30989927da72..406d8424be1a 100644
+--- a/lib/util/substitute.c
++++ b/lib/util/substitute.c
+@@ -25,6 +25,8 @@
+ #include "system/locale.h"
+ #include "debug.h"
+ #ifndef SAMBA_UTIL_CORE_ONLY
++#include "lib/util/fault.h"
++#include "lib/util/talloc_stack.h"
+ #include "charset/charset.h"
+ #else
+ #include "charset_compat.h"
+@@ -297,3 +299,261 @@ char *talloc_all_string_sub(TALLOC_CTX *ctx,
+ return talloc_string_sub2(ctx, src, pattern, insert,
+ false, false, false);
+ }
++
++#ifndef SAMBA_UTIL_CORE_ONLY
++
++bool talloc_string_sub_mixed_quoting(const char *full_cmd, char variable_char)
++{
++ /*
++ * Try to make sure talloc_string_sub_unsafe()
++ * won't return NULL, instead talloc_stackframe_pool()
++ * would panic
++ */
++ size_t cmd_len = full_cmd != NULL ? strlen(full_cmd) : 0;
++ size_t pool_size = 512 + cmd_len;
++ TALLOC_CTX *frame = talloc_stackframe_pool(pool_size);
++ char *cmd = NULL;
++ bool modified = false;
++ bool masked = false;
++ bool mixed_fallback = false;
++
++ cmd = talloc_string_sub_unsafe(frame,
++ full_cmd,
++ variable_char,
++ "U", /* unsafe_value */
++ "'\"%", /* unsafe_characters */
++ '_', /* safe_character */
++ "F", /* fallback_value */
++ &modified,
++ &masked,
++ &mixed_fallback);
++ if (cmd == NULL) {
++ mixed_fallback = false;
++ }
++ TALLOC_FREE(frame);
++ return mixed_fallback;
++}
++
++char *talloc_string_sub_unsafe(TALLOC_CTX *mem_ctx,
++ const char *orig_cmd,
++ char variable_char,
++ const char *unsafe_value,
++ const char *unsafe_characters,
++ char safe_character,
++ const char *fallback_value,
++ bool *_modified,
++ bool *_masked,
++ bool *_mixed_fallback)
++{
++ TALLOC_CTX *frame = talloc_stackframe();
++ const char variable[3] =
++ { '%', variable_char, '\0' };
++ const char variable_s_quoted[5] =
++ { '\'', '%', variable_char, '\'', '\0' };
++ const char variable_d_quoted[5] =
++ { '"', '%', variable_char, '"', '\0' };
++ char *cmd = NULL;
++ char *masked_value = NULL;
++ char *quoted_value = NULL;
++ bool has_s_quotes;
++ bool has_d_quotes;
++ bool has_variable;
++ bool has_variable_s_quoted;
++ bool has_variable_d_quoted;
++ bool modified = false;
++ bool masked = false;
++ bool mixed_fallback = false;
++ bool ok;
++
++ /*
++ * The unsafe_characters argument should contain
++ * single and double quotes.
++ * Otherwise We can't safely handle this.
++ */
++ SMB_ASSERT(unsafe_characters != NULL);
++ SMB_ASSERT(strchr(unsafe_characters, '\'') != NULL);
++ SMB_ASSERT(strchr(unsafe_characters, '"') != NULL);
++ SMB_ASSERT(strchr(unsafe_characters, '%') != NULL);
++
++ cmd = talloc_strdup(mem_ctx, orig_cmd);
++ if (cmd == NULL) {
++ TALLOC_FREE(frame);
++ return NULL;
++ }
++ cmd = talloc_steal(frame, cmd);
++
++ has_variable = strstr(orig_cmd, variable) != NULL;
++ if (!has_variable) {
++ /*
++ * Nothing to do...
++ */
++ goto done;
++ }
++ modified = true;
++
++ /*
++ * Replace all unsafe characters as well as control
++ * characters.
++ *
++ * Note that we start with masked_value = "%u"
++ * and then replace "%u" with unsafe_value,
++ * as a result we have a masked version of
++ * unsafe_value.
++ *
++ * And don't allow option injected like
++ *
++ * '-h value'
++ * '--help value'
++ *
++ */
++ masked_value = talloc_strdup(frame, variable);
++ if (masked_value == NULL) {
++ goto nomem;
++ }
++ ok = realloc_string_sub_raw(&masked_value,
++ variable,
++ unsafe_value,
++ false, /* replace_once */
++ false, /* allow_trailing_dollar */
++ unsafe_characters,
++ safe_character);
++ if (!ok) {
++ goto nomem;
++ }
++ if (masked_value[0] == '-') {
++ masked_value[0] = safe_character;
++ }
++ masked = strcmp(masked_value, unsafe_value) != 0;
++
++retry:
++
++ has_s_quotes = strchr(cmd, '\'') != NULL;
++ has_d_quotes = strchr(cmd, '"') != NULL;
++ has_variable = strstr(cmd, variable) != NULL;
++ has_variable_s_quoted = strstr(cmd, variable_s_quoted) != NULL;
++ has_variable_d_quoted = strstr(cmd, variable_d_quoted) != NULL;
++
++ if (has_variable_s_quoted) {
++ /*
++ * In smb.conf we have something like
++ *
++ * some script = /usr/bin/script '%u'
++ *
++ * It is safe to replace '%u' (or '%J' etc, depending
++ * on variable_char) with '<masked_value>' if
++ * masked_value does not contain single quotes. We
++ * have checked that.
++ */
++
++ if (quoted_value == NULL) {
++ quoted_value = talloc_asprintf(frame, "'%s'",
++ masked_value);
++ if (quoted_value == NULL) {
++ goto nomem;
++ }
++ }
++
++ ok = realloc_string_sub_raw(&cmd,
++ variable_s_quoted,
++ quoted_value,
++ false, /* replace_once */
++ false, /* allow_trailing_dollar */
++ NULL, /* unsafe_characters */
++ '\0'); /* safe_character */
++ if (!ok) {
++ goto nomem;
++ }
++
++ goto retry;
++ }
++
++ if (has_variable_d_quoted && !has_s_quotes) {
++ /*
++ * replace the "%u"
++ *
++ * some script = /usr/bin/script "%u"
++ *
++ * with '%u' and try the '%u' -> 'variable' substitution
++ * again.
++ */
++
++ ok = realloc_string_sub_raw(&cmd,
++ variable_d_quoted,
++ variable_s_quoted,
++ false, /* replace_once */
++ false, /* allow_trailing_dollar */
++ NULL, /* unsafe_characters */
++ '\0'); /* safe_character */
++ if (!ok) {
++ goto nomem;
++ }
++
++ goto retry;
++ }
++
++ if (has_variable && !has_s_quotes && !has_d_quotes) {
++ /*
++ * In this case:
++ *
++ * some script = /usr/bin/script %u
++ *
++ * we can safely substitute %u -> '%u' and try the
++ * single quote test again.
++ */
++
++ ok = realloc_string_sub_raw(&cmd,
++ variable,
++ variable_s_quoted,
++ false, /* replace_once */
++ false, /* allow_trailing_dollar */
++ NULL, /* unsafe_characters */
++ '\0'); /* safe_character */
++ if (!ok) {
++ goto nomem;
++ }
++
++ goto retry;
++ }
++
++ if (has_variable) {
++ /*
++ * There are single or double quotes, but not tightly
++ * bound around a %u.
++ *
++ * Or there's a mix of single and double quotes.
++ *
++ * We just use a generic fallback value.
++ * and let the caller warn about this
++ * and give the admin a hind to fix the smb.conf
++ * option.
++ */
++ mixed_fallback = true;
++
++ ok = realloc_string_sub_raw(&cmd,
++ variable,
++ fallback_value,
++ false, /* replace_once */
++ false, /* allow_trailing_dollar */
++ NULL, /* unsafe_characters */
++ '\0'); /* safe_character */
++ if (!ok) {
++ goto nomem;
++ }
++ }
++
++done:
++ *_modified = modified;
++ *_masked = masked;
++ *_mixed_fallback = mixed_fallback;
++ cmd = talloc_steal(mem_ctx, cmd);
++ TALLOC_FREE(frame);
++ return cmd;
++
++nomem:
++ *_modified = false;
++ *_masked = false;
++ *_mixed_fallback = false;
++ TALLOC_FREE(frame);
++ return NULL;
++}
++#endif /* ! SAMBA_UTIL_CORE_ONLY */
+diff --git a/lib/util/substitute.h b/lib/util/substitute.h
+index 41f56c73ba2c..b8205055da1e 100644
+--- a/lib/util/substitute.h
++++ b/lib/util/substitute.h
+@@ -83,4 +83,21 @@ char *talloc_all_string_sub(TALLOC_CTX *ctx,
+ const char *src,
+ const char *pattern,
+ const char *insert);
++
++#ifndef SAMBA_UTIL_CORE_ONLY
++bool talloc_string_sub_mixed_quoting(const char *full_cmd, char variable_char);
++
++char *talloc_string_sub_unsafe(TALLOC_CTX *mem_ctx,
++ const char *orig_cmd,
++ char variable_char,
++ const char *unsafe_value,
++ const char *unsafe_characters,
++ char safe_character,
++ const char *fallback_value,
++ bool *_modified,
++ bool *_masked,
++ bool *_mixed_fallback);
++
++#endif /* ! SAMBA_UTIL_CORE_ONLY */
++
+ #endif /* _SAMBA_SUBSTITUTE_H_ */
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,94 @@
+From 6dce1833a5d27f82a9b133601ce7f749f3be08ec Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Thu, 23 Apr 2026 18:56:21 +0200
+Subject: [PATCH] CVE-2026-4408: lib/util: introduce
+ strstr_for_invalid_account_characters()
+
+This splits out the logic from samaccountname_bad_chars_check()
+in source4/dsdb/samdb/ldb_modules/samldb.c, this will be used
+in other places soon.
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/6dce1833a5d27f82a9b133601ce7f749f3be08ec]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 6dce1833a5d27f82a9b133601ce7f749f3be08ec)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ lib/util/samba_util.h | 9 +++++++++
+ lib/util/util_str.c | 38 ++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 47 insertions(+)
+
+diff --git a/lib/util/samba_util.h b/lib/util/samba_util.h
+index 03dee5c61379..ea741b51c58f 100644
+--- a/lib/util/samba_util.h
++++ b/lib/util/samba_util.h
+@@ -303,6 +303,15 @@ _PUBLIC_ bool set_boolean(const char *boolean_string, bool *boolean);
+ */
+ _PUBLIC_ bool conv_str_bool(const char * str, bool * val);
+
++/**
++ * Returns a pointer to the first invalid character in name.
++ *
++ * Passing a NULL pointer as name is not allowed!
++ *
++ * This returns NULL for a valid account name.
++ **/
++_PUBLIC_ const char *strstr_for_invalid_account_characters(const char *name);
++
+ /**
+ * Convert a size specification like 16K into an integral number of bytes.
+ **/
+diff --git a/lib/util/util_str.c b/lib/util/util_str.c
+index 7c1d15dbeb0b..c4eda4f49f38 100644
+--- a/lib/util/util_str.c
++++ b/lib/util/util_str.c
+@@ -305,3 +305,41 @@ _PUBLIC_ bool set_boolean(const char *boolean_string, bool *boolean)
+ }
+ return false;
+ }
++
++_PUBLIC_ const char *strstr_for_invalid_account_characters(const char *name)
++{
++ /*
++ * Return a pointer to the first invalid character in the
++ * sAMAccountName, or NULL if the whole name is valid.
++ *
++ * The rules here are based on
++ *
++ * https://social.technet.microsoft.com/wiki/contents/articles/11216.active-directory-requirements-for-creating-objects.aspx
++ */
++ size_t i;
++
++ for (i = 0; name[i] != '\0'; i++) {
++ uint8_t c = name[i];
++ const char *p = NULL;
++
++ if (iscntrl(c)) {
++ return &name[i];
++ }
++
++ p = strchr("\"[]:;|=+*?<>/\\,", c);
++ if (p != NULL) {
++ return &name[i];
++ }
++ }
++
++ if (i == 0) {
++ return &name[i];
++ }
++
++ if (name[i - 1] == '.') {
++ i -= 1;
++ return &name[i];
++ }
++
++ return NULL;
++}
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,47 @@
+From 8f28ca0b8abccf30f479133cc78f9a72500ab366 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Mon, 11 May 2026 20:21:36 +0200
+Subject: [PATCH] CVE-2026-4408: s3:samr-server: only allow
+ _samr_ValidatePassword as DC
+
+This is only supported with 'rpc start on demand helpers = no',
+as it needs ncacn_ip_tcp, but we better also restrict it to DCs.
+
+Maybe only FreeIPA needs it as NT4 didn't support ncacn_ip_tcp.
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/8f28ca0b8abccf30f479133cc78f9a72500ab366]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 8f28ca0b8abccf30f479133cc78f9a72500ab366)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ source3/rpc_server/samr/srv_samr_nt.c | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/source3/rpc_server/samr/srv_samr_nt.c b/source3/rpc_server/samr/srv_samr_nt.c
+index e0d0875bd5da..3937dbe3f32e 100644
+--- a/source3/rpc_server/samr/srv_samr_nt.c
++++ b/source3/rpc_server/samr/srv_samr_nt.c
+@@ -7500,6 +7500,14 @@ NTSTATUS _samr_ValidatePassword(struct pipes_struct *p,
+ return NT_STATUS_ACCESS_DENIED;
+ }
+
++ if (lp_server_role() <= ROLE_DOMAIN_MEMBER) {
++ /*
++ * We only want this on DCs
++ */
++ p->fault_state = DCERPC_FAULT_ACCESS_DENIED;
++ return NT_STATUS_ACCESS_DENIED;
++ }
++
+ if (r->in.level < 1 || r->in.level > 3) {
+ return NT_STATUS_INVALID_INFO_CLASS;
+ }
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,174 @@
+From 1c5146ddfc736e9d790bd91f3124c6fba6847bb3 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Wed, 18 Mar 2026 12:24:47 +0100
+Subject: [PATCH] CVE-2026-4408: s3:samr-server: deny, mask and/or single
+ quote username to 'check password script'
+
+We pass this on to the check password script, prevent remote command
+execution.
+
+We now try to autodetect if we could implicitly use '%u' for the
+replacement and fallback to a fixed fallback username.
+
+Admins should make use of SAMBA_CPS_ACCOUNT_NAME
+instead of passing '%u' to 'check password script'
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+Pair-Programmed-With: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/1c5146ddfc736e9d790bd91f3124c6fba6847bb3]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 1c5146ddfc736e9d790bd91f3124c6fba6847bb3)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ source3/rpc_server/samr/srv_samr_chgpasswd.c | 110 +++++++++++++++++--
+ 1 file changed, 101 insertions(+), 9 deletions(-)
+
+diff --git a/source3/rpc_server/samr/srv_samr_chgpasswd.c b/source3/rpc_server/samr/srv_samr_chgpasswd.c
+index 6c0c0da0cfc3..9afb8799aea0 100644
+--- a/source3/rpc_server/samr/srv_samr_chgpasswd.c
++++ b/source3/rpc_server/samr/srv_samr_chgpasswd.c
+@@ -54,6 +54,7 @@
+ #include "passdb.h"
+ #include "auth.h"
+ #include "lib/util/sys_rw.h"
++#include "lib/util/util_str_escape.h"
+ #include "librpc/rpc/dcerpc_samr.h"
+
+ #include "lib/crypto/gnutls_helpers.h"
+@@ -1008,27 +1009,118 @@ static bool check_passwd_history(struct samu *sampass, const char *plaintext)
+ /***********************************************************
+ ************************************************************/
+
++static NTSTATUS check_password_complexity_internal(TALLOC_CTX *tosctx,
++ const char *orig_cmd,
++ const char *username,
++ char **cmd_out)
++{
++ const char *fallback_username = "__CVE-2026-4408_FallbackUsername__";
++ const char *inv = NULL;
++ char *cmd = NULL;
++ bool modified = false;
++ bool masked = false;
++ bool mixed_fallback = false;
++
++ *cmd_out = NULL;
++
++ if (username == NULL) {
++ return NT_STATUS_INVALID_USER_PRINCIPAL_NAME;
++ }
++
++ /*
++ * This catches invalid characters in account names
++ * which might be problematic passing to a shell script.
++ */
++ inv = strstr_for_invalid_account_characters(username);
++ if (inv != NULL) {
++ char *le_username = log_escape(tosctx, username);
++
++ DBG_WARNING("username '%s' has invalid or dangerous characters\n",
++ le_username);
++
++ TALLOC_FREE(le_username);
++
++ return NT_STATUS_INVALID_USER_PRINCIPAL_NAME;
++ }
++
++ /*
++ * This masks the remaining unsafe characters which
++ * are not already caught by strstr_for_invalid_account_characters()
++ * with '_'.
++ *
++ * Then it replaces %u with an single quoted
++ * and/or shell escaped version of the masked username.
++ */
++ cmd = talloc_string_sub_unsafe(tosctx,
++ orig_cmd,
++ 'u',
++ username,
++ STRING_SUB_UNSAFE_CHARACTERS,
++ '_',
++ fallback_username,
++ &modified,
++ &masked,
++ &mixed_fallback);
++ if (cmd == NULL) {
++ return NT_STATUS_NO_MEMORY;
++ }
++
++ /*
++ * Now warn about unexpected values
++ */
++
++ if (mixed_fallback) {
++ D_WARNING("CVE-2026-4408: "
++ "strange quoting in 'check password script', "
++ "falling back to replace %%u with %s, "
++ "use testparm to fix the configuration\n",
++ fallback_username);
++ D_WARNING("CVE-2026-4408: "
++ "You should use '%%u', or SAMBA_CPS_ACCOUNT_NAME "
++ "inside of 'check password script'.\n");
++ } else if (masked) {
++ char *le_username = log_escape(tosctx, username);
++
++ D_WARNING("CVE-2026-4408: "
++ "replaced %%u with masked value instead of: %s\n",
++ le_username);
++ D_WARNING("CVE-2026-4408: "
++ "You should use SAMBA_CPS_ACCOUNT_NAME inside "
++ "'check password script' instead of %%u.\n");
++
++ TALLOC_FREE(le_username);
++ }
++
++ *cmd_out = cmd;
++ return NT_STATUS_OK;
++}
++
++
+ NTSTATUS check_password_complexity(const char *username,
+ const char *fullname,
+ const char *password,
+ enum samPwdChangeReason *samr_reject_reason)
+ {
++ int check_ret;
++ NTSTATUS status;
+ TALLOC_CTX *tosctx = talloc_tos();
+ const struct loadparm_substitution *lp_sub =
+ loadparm_s3_global_substitution();
+- int check_ret;
+- char *cmd;
++ const char *orig_cmd = NULL;
++ char *cmd = NULL;
+
+- /* Use external script to check password complexity */
+- if ((lp_check_password_script(tosctx, lp_sub) == NULL)
+- || (*(lp_check_password_script(tosctx, lp_sub)) == '\0')){
++ orig_cmd = lp_check_password_script(tosctx, lp_sub);
++ if (orig_cmd == NULL || orig_cmd[0] == '\0') {
+ return NT_STATUS_OK;
+ }
+
+- cmd = talloc_string_sub(tosctx, lp_check_password_script(tosctx, lp_sub), "%u",
+- username);
+- if (!cmd) {
+- return NT_STATUS_PASSWORD_RESTRICTION;
++ /* note we don't use 'fullname' or 'password' here */
++ status = check_password_complexity_internal(tosctx,
++ orig_cmd,
++ username,
++ &cmd);
++ if (!NT_STATUS_IS_OK(status)) {
++ return status;
+ }
+
+ check_ret = setenv("SAMBA_CPS_ACCOUNT_NAME", username, 1);
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,59 @@
+From 67ad724e22f3724d5e07eaa8f25eb527aa417599 Mon Sep 17 00:00:00 2001
+From: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+Date: Sat, 2 May 2026 22:12:38 +1200
+Subject: [PATCH] CVE-2026-4408: s3:samr-server: make
+ check_password_complexity_internal() non-static, for easier testing
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/67ad724e22f3724d5e07eaa8f25eb527aa417599]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 67ad724e22f3724d5e07eaa8f25eb527aa417599)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ source3/rpc_server/samr/srv_samr_chgpasswd.c | 8 ++++----
+ source3/rpc_server/samr/srv_samr_util.h | 5 +++++
+ 2 files changed, 9 insertions(+), 4 deletions(-)
+
+diff --git a/source3/rpc_server/samr/srv_samr_chgpasswd.c b/source3/rpc_server/samr/srv_samr_chgpasswd.c
+index 9afb8799aea0..3f48da47a5bd 100644
+--- a/source3/rpc_server/samr/srv_samr_chgpasswd.c
++++ b/source3/rpc_server/samr/srv_samr_chgpasswd.c
+@@ -1009,10 +1009,10 @@ static bool check_passwd_history(struct samu *sampass, const char *plaintext)
+ /***********************************************************
+ ************************************************************/
+
+-static NTSTATUS check_password_complexity_internal(TALLOC_CTX *tosctx,
+- const char *orig_cmd,
+- const char *username,
+- char **cmd_out)
++NTSTATUS check_password_complexity_internal(TALLOC_CTX *tosctx,
++ const char *orig_cmd,
++ const char *username,
++ char **cmd_out)
+ {
+ const char *fallback_username = "__CVE-2026-4408_FallbackUsername__";
+ const char *inv = NULL;
+diff --git a/source3/rpc_server/samr/srv_samr_util.h b/source3/rpc_server/samr/srv_samr_util.h
+index 5e839ac77c01..a3a22012858b 100644
+--- a/source3/rpc_server/samr/srv_samr_util.h
++++ b/source3/rpc_server/samr/srv_samr_util.h
+@@ -79,6 +79,11 @@ NTSTATUS pass_oem_change(char *user, const char *rhost,
+ uchar password_encrypted_with_nt_hash[516],
+ const uchar old_nt_hash_encrypted[16],
+ enum samPwdChangeReason *reject_reason);
++
++NTSTATUS check_password_complexity_internal(TALLOC_CTX *mem_ctx,
++ const char *_orig_cmd,
++ const char *username,
++ char **cmd_out);
+ NTSTATUS check_password_complexity(const char *username,
+ const char *fullname,
+ const char *password,
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,1108 @@
+From ebd4edda32d949e10e531939b7a4e19b2306ff64 Mon Sep 17 00:00:00 2001
+From: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+Date: Sat, 9 May 2026 22:02:47 +1200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: lib/util: add
+ test_string_sub unittests
+
+This demonstrates the logic of talloc_string_sub_{mixed_quoting,unsafe}()
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/ebd4edda32d949e10e531939b7a4e19b2306ff64]
+
+Pair-Programmed-With: Stefan Metzmacher <metze@samba.org>
+
+Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+(cherry picked from commit ebd4edda32d949e10e531939b7a4e19b2306ff64)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ lib/util/tests/test_string_sub.c | 1044 ++++++++++++++++++++++++++++++
+ lib/util/wscript_build | 6 +
+ selftest/tests.py | 2 +
+ 3 files changed, 1052 insertions(+)
+ create mode 100644 lib/util/tests/test_string_sub.c
+
+diff --git a/lib/util/tests/test_string_sub.c b/lib/util/tests/test_string_sub.c
+new file mode 100644
+index 000000000000..da97c1c936ca
+--- /dev/null
++++ b/lib/util/tests/test_string_sub.c
+@@ -0,0 +1,1044 @@
++
++#include <stdarg.h>
++#include <stddef.h>
++#include <stdint.h>
++#include <setjmp.h>
++#include <sys/stat.h>
++#include "replace.h"
++#include <cmocka.h>
++#include "talloc.h"
++
++#include "../substitute.h"
++
++/* set _DEBUG_VERBOSE to print more. */
++#define _DEBUG_VERBOSE
++
++#ifdef _DEBUG_VERBOSE
++#define debug_message(...) print_message(__VA_ARGS__)
++#else
++#define debug_message(...) /* debug_message */
++#endif
++
++
++static int setup_talloc_context(void **state)
++{
++ TALLOC_CTX *mem_ctx = talloc_new(NULL);
++ *state = mem_ctx;
++ return 0;
++}
++
++static int teardown_talloc_context(void **state)
++{
++ TALLOC_CTX *mem_ctx = *state;
++ TALLOC_FREE(mem_ctx);
++ return 0;
++}
++
++struct cmd_expansion {
++ const char *lp_cmd;
++ const char *username;
++ const char *result_cmd;
++ bool modified;
++ bool masked;
++ bool mixed_fallback;
++};
++
++static void _test_talloc_string_sub_unsafe(void **state,
++ struct cmd_expansion expansions[],
++ size_t n_expansions,
++ const char *unsafe_characters)
++{
++ TALLOC_CTX *mem_ctx = *state;
++ size_t i;
++
++ for (i = 0; i < n_expansions; i++) {
++ struct cmd_expansion t = expansions[i];
++ char *result_cmd = NULL;
++ bool masked;
++ bool mixed_fallback;
++ bool modified;
++ bool flags_correct;
++ bool mixed;
++ int cmp;
++
++ mixed = talloc_string_sub_mixed_quoting(t.lp_cmd, 'u');
++
++ result_cmd = talloc_string_sub_unsafe(mem_ctx,
++ t.lp_cmd,
++ 'u',
++ t.username,
++ unsafe_characters,
++ '_',
++ "FallbackUsername",
++ &modified,
++ &masked,
++ &mixed_fallback);
++ assert_ptr_not_equal(result_cmd, NULL);
++ assert_ptr_not_equal(t.result_cmd, NULL);
++
++ cmp = strcmp(t.result_cmd, result_cmd);
++ flags_correct = (modified == t.modified &&
++ masked == t.masked &&
++ mixed_fallback == t.mixed_fallback);
++
++ if (cmp == 0) {
++ debug_message("[%zu] «%s» «%s» -> «%s»; AS EXPECTED\n",
++ i, t.lp_cmd,
++ t.username,
++ result_cmd);
++ } else {
++ debug_message("[%zu] «%s» «%s»; "
++ "expected [%zu] «%s» got [%zu] «%s»\033[1;31m BAD! \033[0m\n",
++ i, t.lp_cmd,
++ t.username,
++ strlen(t.result_cmd), t.result_cmd,
++ strlen(result_cmd), result_cmd);
++ }
++ assert_int_equal(cmp, 0);
++ if (!flags_correct) {
++ debug_message("[%zu] ", i);
++#define _FLAG(x) debug_message((t. x == x) ? "%s: %s √; ": \
++ "%s \033[1;31m expected %s \033[0m; ", \
++ #x, t.x ? "true": "false");
++ _FLAG(modified);
++ _FLAG(masked);
++ _FLAG(mixed_fallback);
++ debug_message("\n");
++ }
++ assert_int_equal(flags_correct, true);
++ if (mixed_fallback != mixed) {
++ debug_message("[%zu] %s mixed \033[1;31m expected %s \033[0m; ",
++ i, t.lp_cmd,
++ mixed_fallback ? "true": "false");
++ }
++ assert_int_equal(mixed_fallback, mixed);
++#undef _FLAG
++ }
++ debug_message("ALL correct\n");
++}
++
++static void test_talloc_string_sub_unsafe(void **state)
++{
++ const char *unsafe_characters = STRING_SUB_UNSAFE_CHARACTERS;
++
++ static struct cmd_expansion expansions[] = {
++ {
++ "/bin/echo \"bob'",
++ "bob",
++ "/bin/echo \"bob'",
++ false,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "bob",
++ "/bin/echo 'bob'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "bob",
++ "/bin/echo 'bob'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "bob'",
++ "/bin/echo 'bob_'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "bob'''",
++ "/bin/echo 'bob___'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "bob\'",
++ "/bin/echo 'bob_'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo '%u",
++ "bob bob bob",
++ "/bin/echo 'FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo \"%u\"",
++ " ",
++ "/bin/echo ' '",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo \"--uu=%u\"",
++ "bob",
++ "/bin/echo \"--uu=FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo \"--uu=%u\"",
++ "bob !0",
++ "/bin/echo \"--uu=FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo %u",
++ "!0",
++ "/bin/echo '!0'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo \"--uu=%u\"",
++ "bob \\",
++ "/bin/echo \"--uu=FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "bob >> x",
++ "/bin/echo --uu='bob __ x'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo '--uu=%u\"",
++ "bob",
++ "/bin/echo '--uu=FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "bob",
++ "/bin/echo --uu='bob'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo --uu'=%u'",
++ "bob",
++ "/bin/echo --uu'=FallbackUsername'",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo --uu'=%u'",
++ "`ls`",
++ "/bin/echo --uu'=FallbackUsername'",
++ true,
++ true,
++ true,
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "u%u%u%u%u",
++ "/bin/echo --uu='u_u_u_u_u'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "$(ls)",
++ "/bin/echo --uu='_(ls)'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "`ls`",
++ "/bin/echo --uu='_ls_'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo --uu='1' %u",
++ "`ls`",
++ "/bin/echo --uu='1' FallbackUsername",
++ true,
++ true,
++ true,
++ },
++ {
++ "/bin/echo --uu=\"'%u'\"",
++ "bob",
++ "/bin/echo --uu=\"'bob'\"",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo --uu='%u' --yy='%u' '%u' %u",
++ "bob",
++ "/bin/echo --uu='bob' --yy='bob' 'bob' FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo --uu=%u%u%u'' %user 50%u",
++ "bob",
++ "/bin/echo --uu=FallbackUsernameFallbackUsernameFallbackUsername'' FallbackUsernameser 50FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo %u",
++ "!!",
++ "/bin/echo '!!'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ ">xxx",
++ "/bin/echo '_xxx'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "3",
++ "/bin/echo '3'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "3$",
++ "/bin/echo '3_'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "comp$",
++ "/bin/echo 'comp_'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "3$3",
++ "/bin/echo '3_3'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "q $3",
++ "/bin/echo 'q _3'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo '%u",
++ "q $3",
++ "/bin/echo 'FallbackUsername",
++ true,
++ true,
++ true,
++ },
++ {
++ "/bin/echo -s '%u' %u",
++ "āāā",
++ "/bin/echo -s 'āāā' FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo -s '%u' %u",
++ "-āāā",
++ "/bin/echo -s '_āāā' FallbackUsername",
++ true,
++ true,
++ true,
++ },
++ {
++ "/bin/echo -s %u",
++ "āāā",
++ "/bin/echo -s 'āāā'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo -s %u",
++ "a -a",
++ "/bin/echo -s 'a -a'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo -s=%u %u",
++ "ā -a",
++ "/bin/echo -s='ā -a' 'ā -a'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo -s=\"%u %u\"",
++ "ā -a",
++ "/bin/echo -s=\"FallbackUsername FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo -m='fridge' %u",
++ "ā -ß",
++ "/bin/echo -m='fridge' FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo -m='fridge' %u",
++ "-ā -a",
++ "/bin/echo -m='fridge' FallbackUsername",
++ true,
++ true,
++ true,
++ },
++ {
++ "/bin/echo %u",
++ "-n",
++ "/bin/echo '_n'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "o'clock",
++ "/bin/echo 'o_clock'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo \"bob'",
++ "bob",
++ "/bin/echo \"bob'",
++ false,
++ false,
++ false,
++ },
++ {
++ "/bin/echo \"%u\"",
++ "%u",
++ "/bin/echo '_u'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo \"$(ls)\"",
++ "%u",
++ "/bin/echo \"$(ls)\"",
++ false,
++ false,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "\\",
++ "/bin/echo '\\'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "\\",
++ "/bin/echo '\\'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo \"%u\"",
++ "\\",
++ "/bin/echo '\\'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo \"%u\" %u",
++ "\\",
++ "/bin/echo '\\' FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo '%u' \"%u\" %u",
++ "\\",
++ "/bin/echo '\\' \"FallbackUsername\" FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo '%u' \"%u\"",
++ "bob",
++ "/bin/echo 'bob' \"FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ };
++
++ _test_talloc_string_sub_unsafe(state,
++ expansions,
++ ARRAY_SIZE(expansions),
++ unsafe_characters);
++}
++
++static void test_talloc_string_sub_unsafe_minimal_unsafe_chars(void **state)
++{
++ const char *unsafe_characters = "\"'%";
++
++ static struct cmd_expansion expansions[] = {
++ {
++ "/bin/echo \"bob'",
++ "bob",
++ "/bin/echo \"bob'",
++ false,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "bob",
++ "/bin/echo 'bob'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "bob",
++ "/bin/echo 'bob'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "bob'",
++ "/bin/echo 'bob_'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "bob'''",
++ "/bin/echo 'bob___'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "bob\'",
++ "/bin/echo 'bob_'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo '%u",
++ "bob bob bob",
++ "/bin/echo 'FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo \"%u\"",
++ " ",
++ "/bin/echo ' '",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo \"--uu=%u\"",
++ "bob",
++ "/bin/echo \"--uu=FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo \"--uu=%u\"",
++ "bob !0",
++ "/bin/echo \"--uu=FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo %u",
++ "!0",
++ "/bin/echo '!0'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo \"--uu=%u\"",
++ "bob \\",
++ "/bin/echo \"--uu=FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "bob >> x",
++ "/bin/echo --uu='bob >> x'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '--uu=%u\"",
++ "bob",
++ "/bin/echo '--uu=FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "bob",
++ "/bin/echo --uu='bob'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo --uu'=%u'",
++ "bob",
++ "/bin/echo --uu'=FallbackUsername'",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo --uu'=%u'",
++ "`ls`",
++ "/bin/echo --uu'=FallbackUsername'",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "u%u%u%u%u",
++ "/bin/echo --uu='u_u_u_u_u'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "$(ls)",
++ "/bin/echo --uu='$(ls)'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "`ls`",
++ "/bin/echo --uu='`ls`'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo --uu='1' %u",
++ "`ls`",
++ "/bin/echo --uu='1' FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo --uu=\"'%u'\"",
++ "bob",
++ "/bin/echo --uu=\"'bob'\"",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo --uu='%u' --yy='%u' '%u' %u",
++ "bob",
++ "/bin/echo --uu='bob' --yy='bob' 'bob' FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo --uu=%u%u%u'' %user 50%u",
++ "bob",
++ "/bin/echo --uu=FallbackUsernameFallbackUsernameFallbackUsername'' FallbackUsernameser 50FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo %u",
++ "!!",
++ "/bin/echo '!!'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ ">xxx",
++ "/bin/echo '>xxx'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "3",
++ "/bin/echo '3'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "3$",
++ "/bin/echo '3$'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "comp$",
++ "/bin/echo 'comp$'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "3$3",
++ "/bin/echo '3$3'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "q $3",
++ "/bin/echo 'q $3'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '%u",
++ "q $3",
++ "/bin/echo 'FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo -s '%u' %u",
++ "āāā",
++ "/bin/echo -s 'āāā' FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo -s '%u' %u",
++ "-āāā",
++ "/bin/echo -s '_āāā' FallbackUsername",
++ true,
++ true,
++ true,
++ },
++ {
++ "/bin/echo -s %u",
++ "āāā",
++ "/bin/echo -s 'āāā'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo -s %u",
++ "a -a",
++ "/bin/echo -s 'a -a'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo -s=%u %u",
++ "ā -a",
++ "/bin/echo -s='ā -a' 'ā -a'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo -s=\"%u %u\"",
++ "ā -a",
++ "/bin/echo -s=\"FallbackUsername FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo -m='fridge' %u",
++ "ā -ß",
++ "/bin/echo -m='fridge' FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo -m='fridge' %u",
++ "-ā -a",
++ "/bin/echo -m='fridge' FallbackUsername",
++ true,
++ true,
++ true,
++ },
++ {
++ "/bin/echo %u",
++ "-n",
++ "/bin/echo '_n'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "o'clock",
++ "/bin/echo 'o_clock'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo \"bob'",
++ "bob",
++ "/bin/echo \"bob'",
++ false,
++ false,
++ false,
++ },
++ {
++ "/bin/echo \"%u\"",
++ "%u",
++ "/bin/echo '_u'",
++ true,
++ true,
++ false,
++ },
++ {
++ "/bin/echo \"$(ls)\"",
++ "%u",
++ "/bin/echo \"$(ls)\"",
++ false,
++ false,
++ false,
++ },
++ {
++ "/bin/echo %u",
++ "\\",
++ "/bin/echo '\\'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo '%u'",
++ "\\",
++ "/bin/echo '\\'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo \"%u\"",
++ "\\",
++ "/bin/echo '\\'",
++ true,
++ false,
++ false,
++ },
++ {
++ "/bin/echo \"%u\" %u",
++ "\\",
++ "/bin/echo '\\' FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo '%u' \"%u\" %u",
++ "\\",
++ "/bin/echo '\\' \"FallbackUsername\" FallbackUsername",
++ true,
++ false,
++ true,
++ },
++ {
++ "/bin/echo '%u' \"%u\"",
++ "bob",
++ "/bin/echo 'bob' \"FallbackUsername\"",
++ true,
++ false,
++ true,
++ },
++ };
++
++ _test_talloc_string_sub_unsafe(state,
++ expansions,
++ ARRAY_SIZE(expansions),
++ unsafe_characters);
++}
++
++static void test_talloc_string_sub_unsafe_all_mixes(void **state)
++{
++ const char *unsafe_characters = STRING_SUB_UNSAFE_CHARACTERS;
++ size_t i;
++
++ for (i = 0; i < 32; i++) {
++ char in[100] = { 0, };
++ char out[100] = { 0, };
++ struct cmd_expansion expansions[] = {
++ {
++ in,
++ "bob",
++ out,
++ true,
++ false,
++ false,
++ },
++ };
++ bool vsq = i & 1;
++ bool vdq = i & 2;
++ bool v = i & 4;
++ bool sq = i & 8;
++ bool dq = i & 16;
++ char *inp = in;
++ char *outp = out;
++ if (vsq) {
++ inp = stpcpy(inp, "'%u' ");
++ outp = stpcpy(outp, "'bob' ");
++ debug_message("vsq ");
++ }
++ if (vdq) {
++ inp = stpcpy(inp, "\"%u\" ");
++ outp = stpcpy(outp, (vsq || sq) ? "\"FallbackUsername\" " : "'bob' ");
++ debug_message("vdq ");
++ if (vsq || sq) {
++ expansions[0].mixed_fallback = true;
++ }
++ }
++ if (v) {
++ inp = stpcpy(inp, "%u ");
++ outp = stpcpy(outp, (vsq || vdq || sq || dq) ? "FallbackUsername " : "'bob' ");
++ debug_message("v ");
++ if (vsq || vdq || sq || dq) {
++ expansions[0].mixed_fallback = true;
++ }
++ }
++ if (sq) {
++ inp = stpcpy(inp, "' ");
++ outp = stpcpy(outp, "' ");
++ debug_message("sq ");
++ }
++ if (dq) {
++ inp = stpcpy(inp, "\" ");
++ outp = stpcpy(outp, "\" ");
++ debug_message("dq ");
++ }
++ debug_message("(i: %zu)\n", i);
++ *inp = '\0';
++ *outp = '\0';
++ expansions[0].modified = strcmp(in, out) != 0;
++
++ _test_talloc_string_sub_unsafe(state,
++ expansions,
++ ARRAY_SIZE(expansions),
++ unsafe_characters);
++ }
++}
++
++
++int main(void)
++{
++ const struct CMUnitTest tests[] = {
++ cmocka_unit_test(test_talloc_string_sub_unsafe),
++ cmocka_unit_test(test_talloc_string_sub_unsafe_minimal_unsafe_chars),
++ cmocka_unit_test(test_talloc_string_sub_unsafe_all_mixes),
++ };
++ if (!isatty(1)) {
++ cmocka_set_message_output(CM_OUTPUT_SUBUNIT);
++ }
++ return cmocka_run_group_tests(tests,
++ setup_talloc_context,
++ teardown_talloc_context);
++}
+diff --git a/lib/util/wscript_build b/lib/util/wscript_build
+index 9dff0e8925db..c9c04f1aaed3 100644
+--- a/lib/util/wscript_build
++++ b/lib/util/wscript_build
+@@ -420,3 +420,9 @@ else:
+ deps='cmocka replace talloc stable_sort',
+ local_include=False,
+ for_selftest=True)
++
++ bld.SAMBA3_BINARY('test_string_sub',
++ source='tests/test_string_sub.c',
++ deps='''cmocka replace talloc samba-util
++ ''',
++ for_selftest=True)
+diff --git a/selftest/tests.py b/selftest/tests.py
+index 534612296449..71634191dd15 100644
+--- a/selftest/tests.py
++++ b/selftest/tests.py
+@@ -559,6 +559,8 @@ plantestsuite("samba.unittests.sys_rw", "none",
+ [os.path.join(bindir(), "default/lib/util/test_sys_rw")])
+ plantestsuite("samba.unittests.stable_sort", "none",
+ [os.path.join(bindir(), "default/lib/util/test_stable_sort")])
++plantestsuite("samba.unittests.test_string_sub", "none",
++ [os.path.join(bindir(), "test_string_sub")])
+ plantestsuite("samba.unittests.ntlm_check", "none",
+ [os.path.join(bindir(), "default/libcli/auth/test_ntlm_check")])
+ plantestsuite("samba.unittests.gnutls", "none",
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,422 @@
+From 266cd3dc063fdb88a0d0468e8d6f85d6abdecc04 Mon Sep 17 00:00:00 2001
+From: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+Date: Sat, 2 May 2026 22:14:43 +1200
+Subject: [PATCH] CVE-2026-4408: s3:torture: tests for password
+ complexity scripts
+
+This tries to demonstrate the new logic for %u in
+'check password script'.
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/266cd3dc063fdb88a0d0468e8d6f85d6abdecc04]
+
+Pair-Programmed-With: Stefan Metzmacher <metze@samba.org>
+
+Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+(cherry picked from commit 266cd3dc063fdb88a0d0468e8d6f85d6abdecc04)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ selftest/tests.py | 2 +
+ source3/torture/test_rpc_samr.c | 358 ++++++++++++++++++++++++++++++++
+ source3/torture/wscript_build | 6 +
+ 3 files changed, 366 insertions(+)
+ create mode 100644 source3/torture/test_rpc_samr.c
+
+diff --git a/selftest/tests.py b/selftest/tests.py
+index 71634191dd15..817c19aa1249 100644
+--- a/selftest/tests.py
++++ b/selftest/tests.py
+@@ -575,6 +575,8 @@ plantestsuite("samba.unittests.test_oLschema2ldif", "none",
+ [os.path.join(bindir(), "default/source4/utils/oLschema2ldif/test_oLschema2ldif")])
+ plantestsuite("samba.unittests.auth.sam", "none",
+ [os.path.join(bindir(), "test_auth_sam")])
++plantestsuite("samba.unittests.test_rpc_samr", "none",
++ [os.path.join(bindir(), "test_rpc_samr")])
+ if have_heimdal_support and not using_system_gssapi:
+ plantestsuite("samba.unittests.auth.heimdal_gensec_unwrap_des", "none",
+ [valgrindify(os.path.join(bindir(), "test_heimdal_gensec_unwrap_des"))])
+diff --git a/source3/torture/test_rpc_samr.c b/source3/torture/test_rpc_samr.c
+new file mode 100644
+index 000000000000..8d4f39852462
+--- /dev/null
++++ b/source3/torture/test_rpc_samr.c
+@@ -0,0 +1,358 @@
++
++#include <stdarg.h>
++#include <stddef.h>
++#include <stdint.h>
++#include <setjmp.h>
++#include <sys/stat.h>
++#include <cmocka.h>
++#include "includes.h"
++#include "talloc.h"
++#include "libcli/util/ntstatus.h"
++#include "../librpc/gen_ndr/samr.h"
++#include "rpc_server/samr/srv_samr_util.h"
++
++/* set SAMR_DEBUG_VERBOSE to true to print more. */
++#define SAMR_DEBUG_VERBOSE true
++
++#if SAMR_DEBUG_VERBOSE
++#define debug_message(...) print_message(__VA_ARGS__)
++#else
++#define debug_message(...) /* debug_message */
++#endif
++
++static int setup_talloc_context(void **state)
++{
++ TALLOC_CTX *mem_ctx = talloc_new(NULL);
++ *state = mem_ctx;
++ return 0;
++}
++
++static int teardown_talloc_context(void **state)
++{
++ TALLOC_CTX *mem_ctx = *state;
++ TALLOC_FREE(mem_ctx);
++ return 0;
++}
++
++struct cmd_expansion {
++ const char *lp_cmd;
++ const char *username;
++ const char *result_cmd;
++ NTSTATUS result_code;
++};
++
++static struct cmd_expansion expansions[] = {
++ {
++ "/bin/echo '%u'",
++ "bob",
++ "/bin/echo 'bob'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo %u",
++ "bob",
++ "/bin/echo 'bob'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo %u",
++ "bob'",
++ "/bin/echo 'bob_'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo %u",
++ "bob\'",
++ "/bin/echo 'bob_'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo %u",
++ "bob'''",
++ "/bin/echo 'bob___'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo %u",
++ "bob*",
++ NULL,
++ NT_STATUS_INVALID_USER_PRINCIPAL_NAME
++ },
++ {
++ "/bin/echo %u",
++ "bob\"",
++ NULL,
++ NT_STATUS_INVALID_USER_PRINCIPAL_NAME
++ },
++ {
++ "/bin/echo '%u",
++ "bob bob bob",
++ "/bin/echo '__CVE-2026-4408_FallbackUsername__",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo \"%u\"",
++ " ",
++ "/bin/echo ' '",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo \"--uu=%u\"",
++ "bob",
++ "/bin/echo \"--uu=__CVE-2026-4408_FallbackUsername__\"",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo \"--uu=%u\"",
++ "bob !0",
++ "/bin/echo \"--uu=__CVE-2026-4408_FallbackUsername__\"",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo %u",
++ "!0",
++ "/bin/echo '!0'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo \"--uu=%u\"",
++ "bob \\",
++ NULL,
++ NT_STATUS_INVALID_USER_PRINCIPAL_NAME
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "bob >> x",
++ NULL,
++ NT_STATUS_INVALID_USER_PRINCIPAL_NAME
++ },
++ {
++ "/bin/echo '--uu=%u\"",
++ "bob",
++ "/bin/echo '--uu=__CVE-2026-4408_FallbackUsername__\"",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "bob",
++ "/bin/echo --uu='bob'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo --uu'=%u'",
++ "bob",
++ "/bin/echo --uu'=__CVE-2026-4408_FallbackUsername__'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo --uu'=%u'",
++ "`ls`",
++ "/bin/echo --uu'=__CVE-2026-4408_FallbackUsername__'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo --uu'=%u'",
++ "$(ls)",
++ "/bin/echo --uu'=__CVE-2026-4408_FallbackUsername__'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo --uu='%u'",
++ "$(ls)",
++ "/bin/echo --uu='_(ls)'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo --uu=\"'%u'\"",
++ "bob",
++ "/bin/echo --uu=\"'bob'\"",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo --uu='%u' --yy='%u' '%u' %u",
++ "bob",
++ "/bin/echo --uu='bob' --yy='bob' 'bob' __CVE-2026-4408_FallbackUsername__",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo --uu=%u%u'' %user 50%u",
++ "bob",
++ "/bin/echo --uu=__CVE-2026-4408_FallbackUsername____CVE-2026-4408_FallbackUsername__'' __CVE-2026-4408_FallbackUsername__ser 50__CVE-2026-4408_FallbackUsername__",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo %u",
++ "!!",
++ "/bin/echo '!!'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo %u",
++ ">xxx",
++ NULL,
++ NT_STATUS_INVALID_USER_PRINCIPAL_NAME
++ },
++ {
++ "/bin/echo %u",
++ "\\",
++ NULL,
++ NT_STATUS_INVALID_USER_PRINCIPAL_NAME
++ },
++ {
++ "/bin/echo %u",
++ "3",
++ "/bin/echo '3'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo '%u'",
++ "3$",
++ "/bin/echo '3_'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo '%u'",
++ "comp$",
++ "/bin/echo 'comp_'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo '%u'",
++ "3$3",
++ "/bin/echo '3_3'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo '%u'",
++ "q $3",
++ "/bin/echo 'q _3'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo -s '%u' %u",
++ "āāā",
++ "/bin/echo -s 'āāā' __CVE-2026-4408_FallbackUsername__",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo -s '%u' %u",
++ "-āāā",
++ "/bin/echo -s '_āāā' __CVE-2026-4408_FallbackUsername__",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo -s %u",
++ "āāā",
++ "/bin/echo -s 'āāā'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo -s %u",
++ "a -a",
++ "/bin/echo -s 'a -a'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo -s=%u %u",
++ "ā -a",
++ "/bin/echo -s='ā -a' 'ā -a'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo -s=\"%u %u\"",
++ "ā -a",
++ "/bin/echo -s=\"__CVE-2026-4408_FallbackUsername__ __CVE-2026-4408_FallbackUsername__\"",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo -m='fridge' %u",
++ "ā -x -ß",
++ "/bin/echo -m='fridge' __CVE-2026-4408_FallbackUsername__",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo -m='fridge' %u",
++ "-ā -a",
++ "/bin/echo -m='fridge' __CVE-2026-4408_FallbackUsername__",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo %u",
++ "-n",
++ "/bin/echo '_n'",
++ NT_STATUS_OK
++ },
++ {
++ "/bin/echo %u",
++ "o'clock",
++ "/bin/echo 'o_clock'",
++ NT_STATUS_OK
++ },
++};
++
++static void test_expansions(void **state)
++{
++ TALLOC_CTX *mem_ctx = *state;
++ size_t i;
++
++ for (i = 0; i < ARRAY_SIZE(expansions); i++) {
++ struct cmd_expansion t = expansions[i];
++ char *result_cmd = NULL;
++ NTSTATUS status;
++
++ status = check_password_complexity_internal(mem_ctx,
++ t.lp_cmd,
++ t.username,
++ &result_cmd);
++ if (NT_STATUS_IS_OK(t.result_code) && NT_STATUS_IS_OK(status)) {
++ int cmp;
++
++ cmp = strcmp(t.result_cmd, result_cmd);
++ if (cmp == 0) {
++ debug_message("[%zu] «%s» «%s» -> «%s», nstatus %s; AS EXPECTED\n",
++ i, t.lp_cmd,
++ t.username,
++ result_cmd,
++ nt_errstr(status));
++ } else {
++ debug_message("[%zu] «%s» «%s», nstatus %s; "
++ "expected «%s» got «%s»\033[1;31m BAD! \033[0m\n",
++ i, t.lp_cmd,
++ t.username,
++ nt_errstr(status),
++ t.result_cmd,
++ result_cmd);
++ }
++ assert_int_equal(cmp, 0);
++ } else if (NT_STATUS_EQUAL(status, t.result_code)) {
++ debug_message("[%zu] «%s» «%s», nstatus %s FAILED AS EXPECTED\n",
++ i, t.lp_cmd,
++ t.username,
++ nt_errstr(status));
++ } else {
++ debug_message("[%zu] «%s» «%s» -> «%s», nstatus %s; "
++ "EXPECTED result «%s» ntstatus %s; \033[1;31m BAD! \033[0m\n",
++ i, t.lp_cmd,
++ t.username,
++ result_cmd,
++ nt_errstr(status),
++ t.result_cmd,
++ nt_errstr(t.result_code));
++ assert_int_equal(true, false);
++ }
++ }
++ debug_message("ALL correct\n");
++}
++
++int main(void)
++{
++ const struct CMUnitTest tests[] = {
++ cmocka_unit_test(test_expansions),
++ };
++ if (!isatty(1)) {
++ cmocka_set_message_output(CM_OUTPUT_SUBUNIT);
++ }
++ return cmocka_run_group_tests(tests,
++ setup_talloc_context,
++ teardown_talloc_context);
++}
+diff --git a/source3/torture/wscript_build b/source3/torture/wscript_build
+index 1d2520099e35..d04008b3df17 100644
+--- a/source3/torture/wscript_build
++++ b/source3/torture/wscript_build
+@@ -133,3 +133,9 @@ bld.SAMBA3_BINARY('vfstest',
+ SMBREADLINE
+ ''',
+ for_selftest=True)
++
++bld.SAMBA3_BINARY('test_rpc_samr',
++ source='test_rpc_samr.c',
++ deps='''RPC_SERVICE cmocka
++ ''',
++ for_selftest=True)
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,55 @@
+From 65a9ac413b03eefc7a48d5536e54177319ca30e3 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Fri, 8 May 2026 23:27:35 +0200
+Subject: [PATCH] CVE-2026-4408: s3:testparm: warn about 'check password
+ script' %u usage
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/65a9ac413b03eefc7a48d5536e54177319ca30e3]
+
+Backport Changes:
+- Adjusted context for Samba 4.19.9 do_global_checks() because the
+ surrounding global-check order differs from the upstream 4.22 patch.
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 65a9ac413b03eefc7a48d5536e54177319ca30e3)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ source3/utils/testparm.c | 13 +++++++++++++
+ 1 file changed, 13 insertions(+)
+
+diff --git a/source3/utils/testparm.c b/source3/utils/testparm.c
+index 02280595d2a0..1a6eb93a2e6d 100644
+--- a/source3/utils/testparm.c
++++ b/source3/utils/testparm.c
+@@ -277,6 +277,7 @@ static int do_global_checks(void)
+ const char *socket_options;
+ const struct loadparm_substitution *lp_sub =
+ loadparm_s3_global_substitution();
++ const char *check_pw_script = NULL;
+
+ fprintf(stderr, "\n");
+
+@@ -699,6 +700,17 @@ static int do_global_checks(void)
+ "CVE-2022-37966\n\n");
+ }
+
++ check_pw_script = lp_check_password_script(talloc_tos(), lp_sub);
++ if (talloc_string_sub_mixed_quoting(check_pw_script, 'u')) {
++ fprintf(stderr,
++ "WARNING: You are using 'check password script' "
++ "with mixed quoting and %%u.\n"
++ "CVE-2026-4408 changed the way %%u substitution works. \n"
++ "You should use the SAMBA_CPS_ACCOUNT_NAME "
++ "environment variable exported to the script, or\n"
++ "at least use single quotes (directly) around '%%u'.\n\n");
++ }
++
+ return ret;
+ }
+
+--
+2.43.0
new file mode 100644
@@ -0,0 +1,52 @@
+From 640f18d1a642264a9777f933dfaae78db6918a5f Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Mon, 11 May 2026 13:52:52 +0200
+Subject: [PATCH] CVE-2026-4408: docs-xml/smbdotconf: clarify '%u' in
+ 'check password script'
+
+Admins should use SAMBA_CPS_ACCOUNT_NAME.
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/640f18d1a642264a9777f933dfaae78db6918a5f]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 640f18d1a642264a9777f933dfaae78db6918a5f)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ docs-xml/smbdotconf/security/checkpasswordscript.xml | 10 ++++++++--
+ 1 file changed, 8 insertions(+), 2 deletions(-)
+
+diff --git a/docs-xml/smbdotconf/security/checkpasswordscript.xml b/docs-xml/smbdotconf/security/checkpasswordscript.xml
+index 18aa2c6d290e..dd162d89f08a 100644
+--- a/docs-xml/smbdotconf/security/checkpasswordscript.xml
++++ b/docs-xml/smbdotconf/security/checkpasswordscript.xml
+@@ -20,8 +20,8 @@
+
+ <itemizedlist>
+ <listitem><para>
+- SAMBA_CPS_ACCOUNT_NAME is always present and contains the sAMAccountName of user,
+- the is the same as the %u substitutions in the none AD DC case.
++ SAMBA_CPS_ACCOUNT_NAME is always present and contains the sAMAccountName of user.
++ It is the same as the '%u' substitutions in the non AD DC case.
+ </para></listitem>
+
+ <listitem><para>
+@@ -33,6 +33,12 @@
+ </para></listitem>
+ </itemizedlist>
+
++ <para>Even on a non AD DC SAMBA_CPS_ACCOUNT_NAME is the preferred way to access the
++ account name, as it contains the raw value provided by the client. If that's not
++ possible you should use single quotes (directly) around %u, e.g. /path/to/somescript '%u',
++ see CVE-2026-4408 for more details.
++ </para>
++
+ <para>Note: In the example directory is a sample program called <command moreinfo="none">crackcheck</command>
+ that uses cracklib to check the password quality.</para>
+
+--
+2.43.0
+
new file mode 100644
@@ -0,0 +1,133 @@
+From 76dcb30911c22d92ca79e9034656b691a2d51df4 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Thu, 23 Apr 2026 18:20:15 +0200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: lib/util: remove unused
+ talloc_strdup(insert) from talloc_string_sub2()
+
+The insert string is not modified, so we do not need to copy it.
+
+This will simplify further changes.
+
+Review with: git show --patience
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/76dcb30911c22d92ca79e9034656b691a2d51df4]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 76dcb30911c22d92ca79e9034656b691a2d51df4)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ lib/util/substitute.c | 57 +++++++++++++++++++------------------------
+ 1 file changed, 25 insertions(+), 32 deletions(-)
+
+diff --git a/lib/util/substitute.c b/lib/util/substitute.c
+index 26362ca77b2c..4a0c58ab3a7f 100644
+--- a/lib/util/substitute.c
++++ b/lib/util/substitute.c
+@@ -157,7 +157,7 @@ char *talloc_string_sub2(TALLOC_CTX *mem_ctx, const char *src,
+ bool replace_once,
+ bool allow_trailing_dollar)
+ {
+- char *p, *in;
++ char *p;
+ char *s;
+ char *string;
+ ssize_t ls,lp,li,ld, i;
+@@ -175,22 +175,32 @@ char *talloc_string_sub2(TALLOC_CTX *mem_ctx, const char *src,
+
+ s = string;
+
+- in = talloc_strdup(mem_ctx, insert);
+- if (!in) {
+- DEBUG(0, ("talloc_string_sub2: ENOMEM\n"));
+- talloc_free(string);
+- return NULL;
+- }
+ ls = (ssize_t)strlen(s);
+ lp = (ssize_t)strlen(pattern);
+ li = (ssize_t)strlen(insert);
+ ld = li - lp;
+
+- for (i=0;i<li;i++) {
+- switch (in[i]) {
++ while ((p = strstr_m(s,pattern))) {
++ if (ld > 0) {
++ int offset = PTR_DIFF(s,string);
++ string = (char *)talloc_realloc_size(mem_ctx, string,
++ ls + ld + 1);
++ if (!string) {
++ DEBUG(0, ("talloc_string_sub: out of "
++ "memory!\n"));
++ return NULL;
++ }
++ p = string + offset + (p - s);
++ }
++ if (li != lp) {
++ memmove(p+li,p+lp,strlen(p+lp)+1);
++ }
++ for (i=0; i<li; i++) {
++ switch (insert[i]) {
+ case '$':
+- /* allow a trailing $
+- * (as in machine accounts) */
++ /*
++ * allow a trailing $ (as in machine accounts)
++ */
+ if (allow_trailing_dollar && (i == li - 1 )) {
+ break;
+ }
+@@ -204,34 +214,18 @@ char *talloc_string_sub2(TALLOC_CTX *mem_ctx, const char *src,
+ case '\r':
+ case '\n':
+ if (remove_unsafe_characters) {
+- in[i] = '_';
+- break;
++ p[i] = '_';
++ continue;
+ }
+
+ FALL_THROUGH;
+ default:
+ /* ok */
+ break;
+- }
+- }
+-
+- while ((p = strstr_m(s,pattern))) {
+- if (ld > 0) {
+- int offset = PTR_DIFF(s,string);
+- string = (char *)talloc_realloc_size(mem_ctx, string,
+- ls + ld + 1);
+- if (!string) {
+- DEBUG(0, ("talloc_string_sub: out of "
+- "memory!\n"));
+- TALLOC_FREE(in);
+- return NULL;
+ }
+- p = string + offset + (p - s);
+- }
+- if (li != lp) {
+- memmove(p+li,p+lp,strlen(p+lp)+1);
++
++ p[i] = insert[i];
+ }
+- memcpy(p, in, li);
+ s = p + li;
+ ls += ld;
+
+@@ -239,7 +233,6 @@ char *talloc_string_sub2(TALLOC_CTX *mem_ctx, const char *src,
+ break;
+ }
+ }
+- TALLOC_FREE(in);
+ return string;
+ }
+
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,208 @@
+From 3032b7efe9d2fd35081ec33d575d01f9ebf6725c Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Thu, 23 Apr 2026 18:20:15 +0200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: lib/util: factor out a
+ mask_unsafe_character() helper function
+
+This moves the logic into a single place and
+makes if more flexible to be used with more
+values than STRING_SUB_UNSAFE_CHARACTERS.
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/3032b7efe9d2fd35081ec33d575d01f9ebf6725c]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 3032b7efe9d2fd35081ec33d575d01f9ebf6725c)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ lib/util/substitute.c | 109 +++++++++++++++++++++---------------------
+ lib/util/substitute.h | 6 ++-
+ 2 files changed, 60 insertions(+), 55 deletions(-)
+
+diff --git a/lib/util/substitute.c b/lib/util/substitute.c
+index 4a0c58ab3a7f..b9fe32e993ec 100644
+--- a/lib/util/substitute.c
++++ b/lib/util/substitute.c
+@@ -35,6 +35,33 @@
+ * @brief Substitute utilities.
+ **/
+
++static inline
++char mask_unsafe_character(char in,
++ bool is_last,
++ bool allow_trailing_dollar,
++ const char *unsafe_characters,
++ char safe_out)
++{
++ const char *unsafe = NULL;
++
++ if (unsafe_characters == NULL) {
++ return in;
++ }
++
++ /* allow a trailing $ (as in machine accounts) */
++ if (allow_trailing_dollar && is_last && in == '$') {
++ return in;
++ }
++
++ unsafe = strchr(unsafe_characters, in);
++ if (unsafe != NULL) {
++ return safe_out;
++ }
++
++ /* ok */
++ return in;
++}
++
+ /**
+ Substitute a string for a pattern in another string. Make sure there is
+ enough room!
+@@ -42,14 +69,16 @@
+ This routine looks for pattern in s and replaces it with
+ insert. It may do multiple replacements or just one.
+
+- Any of " ; ' $ or ` in the insert string are replaced with _
++ Any of STRING_SUB_UNSAFE_CHARACTERS in the insert string are replaced with _
++
+ if len==0 then the string cannot be extended. This is different from the old
+ use of len==0 which was for no length checks to be done.
+ **/
+
+ void string_sub(char *s, const char *pattern, const char *insert, size_t len)
+ {
+- bool remove_unsafe_characters = true;
++ const char *unsafe_characters = STRING_SUB_UNSAFE_CHARACTERS;
++ char safe_character = '_';
+ char *p;
+ size_t ls, lp, li, i;
+
+@@ -76,26 +105,18 @@ void string_sub(char *s, const char *pattern, const char *insert, size_t len)
+ memmove(p+li,p+lp,strlen(p+lp)+1);
+ }
+ for (i=0;i<li;i++) {
+- switch (insert[i]) {
+- case '$':
+- case '`':
+- case '"':
+- case '\'':
+- case ';':
+- case '%':
+- case '\r':
+- case '\n':
+- if ( remove_unsafe_characters ) {
+- p[i] = '_';
+- /* yes this break should be here
+- * since we want to fall throw if
+- * not replacing unsafe chars */
+- break;
+- }
+- FALL_THROUGH;
+- default:
+- p[i] = insert[i];
+- }
++ /*
++ * Without allow_trailing_dollar we don't
++ * need to calculate is_last...
++ */
++ const bool is_last = false;
++ const bool allow_trailing_dollar = false;
++
++ p[i] = mask_unsafe_character(insert[i],
++ is_last,
++ allow_trailing_dollar,
++ unsafe_characters,
++ safe_character);
+ }
+ s = p + li;
+ ls = ls + li - lp;
+@@ -157,9 +178,11 @@ char *talloc_string_sub2(TALLOC_CTX *mem_ctx, const char *src,
+ bool replace_once,
+ bool allow_trailing_dollar)
+ {
+- char *p;
+- char *s;
+- char *string;
++ const char *unsafe_characters = STRING_SUB_UNSAFE_CHARACTERS;
++ const char safe_character = '_';
++ char *p = NULL,
++ char *s = NULL;
++ char *string = NULL;
+ ssize_t ls,lp,li,ld, i;
+
+ if (!insert || !pattern || !*pattern || !src) {
+@@ -195,36 +218,14 @@ char *talloc_string_sub2(TALLOC_CTX *mem_ctx, const char *src,
+ if (li != lp) {
+ memmove(p+li,p+lp,strlen(p+lp)+1);
+ }
+- for (i=0; i<li; i++) {
+- switch (insert[i]) {
+- case '$':
+- /*
+- * allow a trailing $ (as in machine accounts)
+- */
+- if (allow_trailing_dollar && (i == li - 1 )) {
+- break;
+- }
+-
+- FALL_THROUGH;
+- case '`':
+- case '"':
+- case '\'':
+- case ';':
+- case '%':
+- case '\r':
+- case '\n':
+- if (remove_unsafe_characters) {
+- p[i] = '_';
+- continue;
+- }
+-
+- FALL_THROUGH;
+- default:
+- /* ok */
+- break;
+- }
++ for (i=0; i < li; i++) {
++ bool is_last = (i == li - 1);
+
+- p[i] = insert[i];
++ p[i] = mask_unsafe_character(insert[i],
++ is_last,
++ allow_trailing_dollar,
++ unsafe_characters,
++ safe_character);
+ }
+ s = p + li;
+ ls += ld;
+diff --git a/lib/util/substitute.h b/lib/util/substitute.h
+index 3134cfcdea54..e1a82859daca 100644
+--- a/lib/util/substitute.h
++++ b/lib/util/substitute.h
+@@ -26,6 +26,8 @@
+
+ #include <talloc.h>
+
++#define STRING_SUB_UNSAFE_CHARACTERS "$`\"';%\r\n"
++
+ /**
+ Substitute a string for a pattern in another string. Make sure there is
+ enough room!
+@@ -33,7 +35,9 @@
+ This routine looks for pattern in s and replaces it with
+ insert. It may do multiple replacements.
+
+- Any of " ; ' $ or ` in the insert string are replaced with _
++ Any of STRING_SUB_UNSAFE_CHARACTERS (see above) in the
++ insert string are replaced with _
++
+ if len==0 then the string cannot be extended. This is different from the old
+ use of len==0 which was for no length checks to be done.
+ **/
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,179 @@
+From 3f24236a5000402de11d973527eb7d28fd30de19 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Thu, 30 Apr 2026 14:48:26 +0200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: lib/util: split out
+ realloc_string_sub_raw()
+
+This will allow realloc_string_sub2() to use it in order
+to have the logic in one place only.
+
+And it will also allow adjacted callers to be
+more flexible.
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/3f24236a5000402de11d973527eb7d28fd30de19]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 3f24236a5000402de11d973527eb7d28fd30de19)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ lib/util/substitute.c | 85 ++++++++++++++++++++++++++++++-------------
+ lib/util/substitute.h | 18 +++++++++
+ 2 files changed, 78 insertions(+), 25 deletions(-)
+
+diff --git a/lib/util/substitute.c b/lib/util/substitute.c
+index b9fe32e993ec..465aea866055 100644
+--- a/lib/util/substitute.c
++++ b/lib/util/substitute.c
+@@ -171,32 +171,24 @@ _PUBLIC_ void all_string_sub(char *s,const char *pattern,const char *insert, siz
+ * talloc version of string_sub2.
+ */
+
+-char *talloc_string_sub2(TALLOC_CTX *mem_ctx, const char *src,
+- const char *pattern,
+- const char *insert,
+- bool remove_unsafe_characters,
+- bool replace_once,
+- bool allow_trailing_dollar)
++bool realloc_string_sub_raw(char **_string,
++ const char *pattern,
++ const char *insert,
++ bool replace_once,
++ bool allow_trailing_dollar,
++ const char *unsafe_characters,
++ char safe_character)
+ {
+- const char *unsafe_characters = STRING_SUB_UNSAFE_CHARACTERS;
+- const char safe_character = '_';
+- char *p = NULL,
++ char *p = NULL;
+ char *s = NULL;
+ char *string = NULL;
+ ssize_t ls,lp,li,ld, i;
+
+- if (!insert || !pattern || !*pattern || !src) {
+- return NULL;
+- }
+-
+- string = talloc_strdup(mem_ctx, src);
+- if (string == NULL) {
+- DEBUG(0, ("talloc_string_sub2: "
+- "talloc_strdup failed\n"));
+- return NULL;
++ if (!insert || !pattern || !*pattern || !_string|| !*_string) {
++ return false;
+ }
+
+- s = string;
++ s = string = *_string;
+
+ ls = (ssize_t)strlen(s);
+ lp = (ssize_t)strlen(pattern);
+@@ -205,14 +197,13 @@ char *talloc_string_sub2(TALLOC_CTX *mem_ctx, const char *src,
+
+ while ((p = strstr_m(s,pattern))) {
+ if (ld > 0) {
+- int offset = PTR_DIFF(s,string);
+- string = (char *)talloc_realloc_size(mem_ctx, string,
+- ls + ld + 1);
++ ptrdiff_t offset = PTR_DIFF(s,string);
++ string = talloc_realloc(NULL, string, char, ls + ld + 1);
+ if (!string) {
+- DEBUG(0, ("talloc_string_sub: out of "
+- "memory!\n"));
+- return NULL;
++ DBG_ERR("out of memory(realloc)!\n");
++ return false;
+ }
++ *_string = string;
+ p = string + offset + (p - s);
+ }
+ if (li != lp) {
+@@ -234,6 +225,50 @@ char *talloc_string_sub2(TALLOC_CTX *mem_ctx, const char *src,
+ break;
+ }
+ }
++ return true;
++}
++
++char *talloc_string_sub2(TALLOC_CTX *mem_ctx,
++ const char *src,
++ const char *pattern,
++ const char *insert,
++ bool remove_unsafe_characters,
++ bool replace_once,
++ bool allow_trailing_dollar)
++{
++ const char *unsafe_characters = NULL;
++ char safe_character = '\0';
++ char *string = NULL;
++ bool ok;
++
++ if (!insert || !pattern || !*pattern || !src) {
++ return NULL;
++ }
++
++ if (remove_unsafe_characters) {
++ unsafe_characters = STRING_SUB_UNSAFE_CHARACTERS;
++ safe_character = '_';
++ }
++
++ string = talloc_strdup(mem_ctx, src);
++ if (string == NULL) {
++ DBG_ERR("out of memory, talloc_strdup(src)!\n");
++ return NULL;
++ }
++
++ ok = realloc_string_sub_raw(&string,
++ pattern,
++ insert,
++ replace_once,
++ allow_trailing_dollar,
++ unsafe_characters,
++ safe_character);
++ if (!ok) {
++ TALLOC_FREE(string);
++ DBG_ERR("out of memory, realloc_string_sub_raw()!\n");
++ return NULL;
++ }
++
+ return string;
+ }
+
+diff --git a/lib/util/substitute.h b/lib/util/substitute.h
+index e1a82859daca..041a649fd181 100644
+--- a/lib/util/substitute.h
++++ b/lib/util/substitute.h
+@@ -51,6 +51,24 @@ void string_sub(char *s,const char *pattern, const char *insert, size_t len);
+ **/
+ void all_string_sub(char *s,const char *pattern,const char *insert, size_t len);
+
++/*
++ * If unsafe_characters is NULL all characters are allowed,
++ * if unsafe_characters is not NULL all characters caught
++ * by iscntrl() are also replaced by safe_character.
++ *
++ * *_string might be reallocated!
++ *
++ * On error *_string may still be reallocated and
++ * may contain partial replacements.
++ */
++bool realloc_string_sub_raw(char **_string,
++ const char *pattern,
++ const char *insert,
++ bool replace_once,
++ bool allow_trailing_dollar,
++ const char *unsafe_characters,
++ char safe_character);
++
+ char *talloc_string_sub2(TALLOC_CTX *mem_ctx, const char *src,
+ const char *pattern,
+ const char *insert,
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,46 @@
+From 113ba24197ca4e5bd683951f99fa4553a4240e48 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Wed, 6 May 2026 17:23:39 +0200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: s3:lib: fix potential
+ memory leak in talloc_sub_basic()
+
+This makes the code easier to understand...
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/113ba24197ca4e5bd683951f99fa4553a4240e48]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 113ba24197ca4e5bd683951f99fa4553a4240e48)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ source3/lib/substitute.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/source3/lib/substitute.c b/source3/lib/substitute.c
+index 40eb15aee04b..5121fcaac1c4 100644
+--- a/source3/lib/substitute.c
++++ b/source3/lib/substitute.c
+@@ -317,6 +317,7 @@ char *talloc_sub_basic(TALLOC_CTX *mem_ctx,
+ }
+
+ tmp_ctx = talloc_stackframe();
++ a_string = talloc_steal(tmp_ctx, a_string);
+
+ for (s = a_string; (p = strchr_m(s, '%')); s = a_string + (p - b)) {
+
+@@ -478,6 +479,7 @@ error:
+ TALLOC_FREE(a_string);
+
+ done:
++ a_string = talloc_steal(mem_ctx, a_string);
+ TALLOC_FREE(tmp_ctx);
+ return a_string;
+ }
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,131 @@
+From c4a93471622e5d7f8e28073029f3ebfbe22b6288 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Thu, 23 Apr 2026 21:11:27 +0200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: s3:lib: let
+ realloc_string_sub2() use realloc_string_sub_raw()
+
+We don't need this logic more than once!
+
+But we leave the strange calling convention of
+realloc_string_sub2(), where the caller it
+not allowed to use the passed pointer when
+NULL is returned...
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/c4a93471622e5d7f8e28073029f3ebfbe22b6288]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit c4a93471622e5d7f8e28073029f3ebfbe22b6288)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ source3/lib/substitute_generic.c | 81 ++++++++++----------------------
+ 1 file changed, 24 insertions(+), 57 deletions(-)
+
+diff --git a/source3/lib/substitute_generic.c b/source3/lib/substitute_generic.c
+index 26c5ee761f8b..e0639f04eb8e 100644
+--- a/source3/lib/substitute_generic.c
++++ b/source3/lib/substitute_generic.c
+@@ -37,71 +37,38 @@ char *realloc_string_sub2(char *string,
+ bool remove_unsafe_characters,
+ bool allow_trailing_dollar)
+ {
+- char *p, *in;
+- char *s;
+- ssize_t ls,lp,li,ld, i;
++ const char *unsafe_characters = NULL;
++ char safe_character = '\0';
++ bool ok;
+
+ if (!insert || !pattern || !*pattern || !string || !*string)
+ return NULL;
+
+- s = string;
++ if (remove_unsafe_characters) {
++ unsafe_characters = STRING_SUB_UNSAFE_CHARACTERS;
++ safe_character = '_';
++ }
+
+- in = talloc_strdup(talloc_tos(), insert);
+- if (!in) {
+- DEBUG(0, ("realloc_string_sub: out of memory!\n"));
++ ok = realloc_string_sub_raw(&string,
++ pattern,
++ insert,
++ false, /* replace_once */
++ allow_trailing_dollar,
++ unsafe_characters,
++ safe_character);
++ if (!ok) {
++ DBG_ERR("out of memory, realloc_string_sub_raw()!\n");
++ /*
++ * The calling convention of realloc_string_sub2()
++ * is very strange regarding stale string pointers.
++ *
++ * It is assumed the given string was allocated
++ * on talloc_tos(), so we just don't touch
++ * it at all here...
++ */
+ return NULL;
+ }
+- ls = (ssize_t)strlen(s);
+- lp = (ssize_t)strlen(pattern);
+- li = (ssize_t)strlen(insert);
+- ld = li - lp;
+- for (i=0;i<li;i++) {
+- switch (in[i]) {
+- case '$':
+- /* allow a trailing $
+- * (as in machine accounts) */
+- if (allow_trailing_dollar && (i == li - 1 )) {
+- break;
+- }
+- FALL_THROUGH;
+- case '`':
+- case '"':
+- case '\'':
+- case ';':
+- case '%':
+- case '\r':
+- case '\n':
+- if ( remove_unsafe_characters ) {
+- in[i] = '_';
+- break;
+- }
+- FALL_THROUGH;
+- default:
+- /* ok */
+- break;
+- }
+- }
+
+- while ((p = strstr_m(s,pattern))) {
+- if (ld > 0) {
+- int offset = PTR_DIFF(s,string);
+- string = talloc_realloc(NULL, string, char, ls + ld + 1);
+- if (!string) {
+- DEBUG(0, ("realloc_string_sub: "
+- "out of memory!\n"));
+- talloc_free(in);
+- return NULL;
+- }
+- p = string + offset + (p - s);
+- }
+- if (li != lp) {
+- memmove(p+li,p+lp,strlen(p+lp)+1);
+- }
+- memcpy(p, in, li);
+- s = p + li;
+- ls += ld;
+- }
+- talloc_free(in);
+ return string;
+ }
+
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,84 @@
+From 003ff9b49f65d8006330a018da6fe0169a6fdb48 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Thu, 23 Apr 2026 18:21:08 +0200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: lib/util: let
+ mask_unsafe_character() check all control characters
+
+There's no reason to mask only \r and \n.
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/003ff9b49f65d8006330a018da6fe0169a6fdb48]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 003ff9b49f65d8006330a018da6fe0169a6fdb48)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ lib/util/substitute.c | 8 +++++++-
+ lib/util/substitute.h | 6 +++---
+ 2 files changed, 10 insertions(+), 4 deletions(-)
+
+diff --git a/lib/util/substitute.c b/lib/util/substitute.c
+index 465aea866055..30989927da72 100644
+--- a/lib/util/substitute.c
++++ b/lib/util/substitute.c
+@@ -22,6 +22,7 @@
+ */
+
+ #include "replace.h"
++#include "system/locale.h"
+ #include "debug.h"
+ #ifndef SAMBA_UTIL_CORE_ONLY
+ #include "charset/charset.h"
+@@ -53,6 +54,10 @@ char mask_unsafe_character(char in,
+ return in;
+ }
+
++ if (iscntrl(in)) {
++ return safe_out;
++ }
++
+ unsafe = strchr(unsafe_characters, in);
+ if (unsafe != NULL) {
+ return safe_out;
+@@ -69,7 +74,8 @@ char mask_unsafe_character(char in,
+ This routine looks for pattern in s and replaces it with
+ insert. It may do multiple replacements or just one.
+
+- Any of STRING_SUB_UNSAFE_CHARACTERS in the insert string are replaced with _
++ Any of STRING_SUB_UNSAFE_CHARACTERS and any character
++ caught by calling iscntrl() in the insert string are replaced with _
+
+ if len==0 then the string cannot be extended. This is different from the old
+ use of len==0 which was for no length checks to be done.
+diff --git a/lib/util/substitute.h b/lib/util/substitute.h
+index 041a649fd181..b183d864671a 100644
+--- a/lib/util/substitute.h
++++ b/lib/util/substitute.h
+@@ -26,7 +26,7 @@
+
+ #include <talloc.h>
+
+-#define STRING_SUB_UNSAFE_CHARACTERS "$`\"';%\r\n"
++#define STRING_SUB_UNSAFE_CHARACTERS "$`\"';%"
+
+ /**
+ Substitute a string for a pattern in another string. Make sure there is
+@@ -35,8 +35,8 @@
+ This routine looks for pattern in s and replaces it with
+ insert. It may do multiple replacements.
+
+- Any of STRING_SUB_UNSAFE_CHARACTERS (see above) in the
+- insert string are replaced with _
++ Any of STRING_SUB_UNSAFE_CHARACTERS (see above) and any character
++ caught by calling iscntrl() in the insert string are replaced with _
+
+ if len==0 then the string cannot be extended. This is different from the old
+ use of len==0 which was for no length checks to be done.
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,39 @@
+From 5551dd76e92480625f00765f183d753dcb857894 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Thu, 23 Apr 2026 18:21:08 +0200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: lib/util: add more unsafe
+ characters to STRING_SUB_UNSAFE_CHARACTERS
+
+|&<> are unsafe characters for shell processing.
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/5551dd76e92480625f00765f183d753dcb857894]
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 5551dd76e92480625f00765f183d753dcb857894)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ lib/util/substitute.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/lib/util/substitute.h b/lib/util/substitute.h
+index b183d864671a..41f56c73ba2c 100644
+--- a/lib/util/substitute.h
++++ b/lib/util/substitute.h
+@@ -26,7 +26,7 @@
+
+ #include <talloc.h>
+
+-#define STRING_SUB_UNSAFE_CHARACTERS "$`\"';%"
++#define STRING_SUB_UNSAFE_CHARACTERS "$`\"';%|&<>"
+
+ /**
+ Substitute a string for a pattern in another string. Make sure there is
+--
+2.43.0
+
+
new file mode 100644
@@ -0,0 +1,61 @@
+From 0cabcbd24cf2eec692b1a9642447e81c97cc90b7 Mon Sep 17 00:00:00 2001
+From: Stefan Metzmacher <metze@samba.org>
+Date: Fri, 8 May 2026 22:33:32 +0200
+Subject: [PATCH] CVE-2026-4480/CVE-2026-4408: lib/util: let log_escape()
+ make use of iscntrl()
+
+using iscntrl() also handles 0x7F (DEL).
+
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16033
+BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034
+
+CVE: CVE-2026-4408
+Upstream-Status: Backport [https://gitlab.com/samba-team/samba/-/commit/0cabcbd24cf2eec692b1a9642447e81c97cc90b7]
+
+Backport Changes:
+- Adjusted context for Samba 4.19.9 where encoded_length() still takes char;
+ use unsigned char so iscntrl() receives the same safe input type as upstream.
+
+Signed-off-by: Stefan Metzmacher <metze@samba.org>
+Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
+(cherry picked from commit 0cabcbd24cf2eec692b1a9642447e81c97cc90b7)
+Signed-off-by: Ashishkumar Parmar <asparmar@cisco.com>
+---
+ lib/util/util_str_escape.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/lib/util/util_str_escape.c b/lib/util/util_str_escape.c
+index 21f6130a3d60..c6d7a0c9e77a 100644
+--- a/lib/util/util_str_escape.c
++++ b/lib/util/util_str_escape.c
+@@ -18,6 +18,7 @@
+ */
+
+ #include "replace.h"
++#include "system/locale.h"
+ #include "lib/util/debug.h"
+ #include "lib/util/util_str_escape.h"
+
+@@ -26,9 +27,9 @@
+ * Calculate the encoded length of a character for log_escape
+ *
+ */
+-static size_t encoded_length(char c)
++static size_t encoded_length(unsigned char c)
+ {
+- if (c != '\\' && c > 0x1F) {
++ if (c != '\\' && !iscntrl(c)) {
+ return 1;
+ } else {
+ switch (c) {
+@@ -79,7 +80,7 @@ char *log_escape(TALLOC_CTX *frame, const char *in)
+ c = in;
+ e = encoded;
+ while (*c) {
+- if (*c != '\\' && *c > 0x1F) {
++ if (*c != '\\' && !iscntrl((unsigned char)(*c))) {
+ *e++ = *c++;
+ } else {
+ switch (*c) {
+--
+2.43.0
@@ -26,6 +26,24 @@ SRC_URI = "${SAMBA_MIRROR}/stable/samba-${PV}.tar.gz \
file://0007-Deleted-settiong-of-python-to-fix-the-install-confli.patch \
file://CVE-2026-3012_p1.patch \
file://CVE-2026-3012_p2.patch \
+ file://CVE-2026-4408_p1.patch \
+ file://CVE-2026-4408_p2.patch \
+ file://CVE-2026-4408_p3.patch \
+ file://CVE-2026-4408_p4.patch \
+ file://CVE-2026-4408_p5.patch \
+ file://CVE-2026-4408_p6.patch \
+ file://CVE-2026-4408_p7.patch \
+ file://CVE-2026-4408_p8.patch \
+ file://CVE-2026-4408_p9.patch \
+ file://CVE-2026-4408_p10.patch \
+ file://CVE-2026-4408_p11.patch \
+ file://CVE-2026-4408_p12.patch \
+ file://CVE-2026-4408_p13.patch \
+ file://CVE-2026-4408_p14.patch \
+ file://CVE-2026-4408_p15.patch \
+ file://CVE-2026-4408_p16.patch \
+ file://CVE-2026-4408_p17.patch \
+ file://CVE-2026-4408_p18.patch \
"
SRC_URI:append:libc-musl = " \