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[meta-oe,scarthgap,1/2] nginx: backport fix for CVE-2026-42945

Message ID 20260529161332.2176858-1-ngrodriguez@genetec.com
State New
Headers show
Series [meta-oe,scarthgap,1/2] nginx: backport fix for CVE-2026-42945 | expand

Commit Message

Nelson Garcia May 29, 2026, 4:13 p.m. UTC 
A heap memory buffer overflow might occur in a worker process while
handling a specially crafted request by ngx_http_rewrite_module,
potentially resulting in arbitrary code execution.

The is_args flag was set when a rewrite replacement contained query
arguments but was never cleared, causing incorrect URI escaping and
a buffer overrun in subsequent set/if captures.

Fix by resetting e->is_args in ngx_http_script_regex_end_code().

Upstream-Status: Backport [https://github.com/nginx/nginx/commit/524977e7c534e87e5b55739fa74601c9f1102686]
CVE: CVE-2026-42945
Signed-off-by: Nelson Garcia <nelson831002@gmail.com>
---
 .../nginx/nginx-1.24.0/CVE-2026-42945.patch   | 40 +++++++++++++++++++
 .../recipes-httpd/nginx/nginx_1.24.0.bb       |  1 +
 2 files changed, 41 insertions(+)
 create mode 100644 meta-webserver/recipes-httpd/nginx/nginx-1.24.0/CVE-2026-42945.patch
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Patch

diff --git a/meta-webserver/recipes-httpd/nginx/nginx-1.24.0/CVE-2026-42945.patch b/meta-webserver/recipes-httpd/nginx/nginx-1.24.0/CVE-2026-42945.patch
new file mode 100644
index 0000000000..cb476bcd96
--- /dev/null
+++ b/meta-webserver/recipes-httpd/nginx/nginx-1.24.0/CVE-2026-42945.patch
@@ -0,0 +1,40 @@ 
+From 524977e7c534e87e5b55739fa74601c9f1102686 Mon Sep 17 00:00:00 2001
+From: Roman Arutyunyan <arut@nginx.com>
+Date: Tue, 13 May 2026 00:00:00 +0400
+Subject: [PATCH] Rewrite: fixed escaping and possible buffer overrun.
+
+The following code resulted in incorrect escaping of $1 and possible
+segfault:
+
+    location / {
+        rewrite ^(.*) /new?c=1;
+        set $myvar $1;
+        return 200 $myvar;
+    }
+
+If there were arguments in a rewrite's replacement string, the is_args flag
+was set and incorrectly never cleared.  This resulted in escaping applied
+to any captures evaluated afterwards in set or if.  Additionally buffer was
+allocated by ngx_http_script_complex_value_code() without escaping expected,
+thus this also resulted in buffer overrun and possible segfault.
+
+Reported by Leo Lin.
+
+CVE: CVE-2026-42945
+Upstream-Status: Backport [https://github.com/nginx/nginx/commit/524977e7c534e87e5b55739fa74601c9f1102686]
+Signed-off-by: Roman Arutyunyan <arut@nginx.com>
+---
+ src/http/ngx_http_script.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/src/http/ngx_http_script.c b/src/http/ngx_http_script.c
+--- a/src/http/ngx_http_script.c
++++ b/src/http/ngx_http_script.c
+@@ -1202,6 +1202,7 @@ ngx_http_script_regex_end_code(ngx_http_script_engine_t *e)
+ 
+     r = e->request;
+ 
++    e->is_args = 0;
+     e->quote = 0;
+ 
+     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
diff --git a/meta-webserver/recipes-httpd/nginx/nginx_1.24.0.bb b/meta-webserver/recipes-httpd/nginx/nginx_1.24.0.bb
index b732e92b18..c1f277517f 100644
--- a/meta-webserver/recipes-httpd/nginx/nginx_1.24.0.bb
+++ b/meta-webserver/recipes-httpd/nginx/nginx_1.24.0.bb
@@ -9,6 +9,7 @@  SRC_URI:append = " \
                   file://CVE-2026-27654.patch \
                   file://CVE-2026-28753.patch \
                   file://CVE-2026-32647.patch \
+                  file://CVE-2026-42945.patch \
 "
 
 SRC_URI[sha256sum] = "77a2541637b92a621e3ee76776c8b7b40cf6d707e69ba53a940283e30ff2f55d"