new file mode 100644
@@ -0,0 +1,44 @@
+From b5cb1c1781ba5f275485f65855d61faaba6542b2 Mon Sep 17 00:00:00 2001
+From: TristanInSec <tristan.mtn@gmail.com>
+Date: Wed, 15 Apr 2026 14:51:08 -0400
+Subject: [PATCH] packet: check `_libssh2_get_string()` return in `EXT_INFO`
+ handler
+
+The `SSH_MSG_EXT_INFO` handler discards the return values from
+`_libssh2_get_string()` when parsing extension name/value pairs. When
+the buffer is exhausted before all claimed extensions are parsed,
+the loop continues with no-op iterations until `nr_extensions` reaches
+zero.
+
+The `nr_extensions >= 1024` cap limits the worst case, but the loop
+should still break on parse failure for correctness and consistency
+with other parsers in this file (e.g. `SSH_MSG_CHANNEL_OPEN`,
+`SSH_MSG_KEXINIT`) that check `_libssh2_get_string()` return values.
+
+Closes #1864
+
+CVE: CVE-2026-55199
+Upstream-Status: Backport [https://github.com/libssh2/libssh2/commit/17626857d20b3c9a1addfa45979dadcee1cd84a4]
+
+Signed-off-by: Daniel Turull <daniel.turull@ericsson.com>
+---
+ src/packet.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/src/packet.c b/src/packet.c
+index 6da14e9f..ebaddae5 100644
+--- a/src/packet.c
++++ b/src/packet.c
+@@ -868,8 +868,10 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
+
+ nr_extensions -= 1;
+
+- _libssh2_get_string(&buf, &name, &name_len);
+- _libssh2_get_string(&buf, &value, &value_len);
++ if(_libssh2_get_string(&buf, &name, &name_len))
++ break;
++ if(_libssh2_get_string(&buf, &value, &value_len))
++ break;
+
+ if(name && value) {
+ _libssh2_debug((session,
@@ -12,6 +12,7 @@ SRC_URI = "http://www.libssh2.org/download/${BP}.tar.gz \
file://0001-Return-error-if-user-KEX-methods-are-invalid.patch \
file://CVE-2026-7598.patch \
file://CVE-2026-55200.patch \
+ file://CVE-2026-55199.patch \
"
SRC_URI[sha256sum] = "d9ec76cbe34db98eec3539fe2c899d26b0c837cb3eb466a56b0f109cabf658f7"