[scarthgap] [PATCH v2 2/2] libssh2: fix CVE-2026-55199

[<daniel.turull@ericsson.com>]

From: Daniel Turull <daniel.turull@ericsson.com>

Backport patch to fix CVE-2026-55199.
https://nvd.nist.gov/vuln/detail/CVE-2026-55199

Upstream fix:
  https://github.com/libssh2/libssh2/commit/17626857d20b3c9a1addfa45979dadcee1cd84a4

Tested with ptest:
Before: PASSED: 3, FAILED: 0, SKIPPED: 0
After: PASSED: 3, FAILED: 0, SKIPPED: 0

Reviewed-by: Anders Heimer <anders.heimer@est.tech
Signed-off-by: Daniel Turull <daniel.turull@ericsson.com>
---
 .../libssh2/libssh2/CVE-2026-55199.patch      | 44 +++++++++++++++++++
 .../recipes-support/libssh2/libssh2_1.11.1.bb |  1 +
 2 files changed, 45 insertions(+)
 create mode 100644 meta/recipes-support/libssh2/libssh2/CVE-2026-55199.patch

diff --git a/meta/recipes-support/libssh2/libssh2/CVE-2026-55199.patch b/meta/recipes-support/libssh2/libssh2/CVE-2026-55199.patch
new file mode 100644
index 0000000000..81815486ad
--- /dev/null
+++ b/meta/recipes-support/libssh2/libssh2/CVE-2026-55199.patch
@@ -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,
diff --git a/meta/recipes-support/libssh2/libssh2_1.11.1.bb b/meta/recipes-support/libssh2/libssh2_1.11.1.bb
index d6ee97f7ed..960ff71df2 100644
--- a/meta/recipes-support/libssh2/libssh2_1.11.1.bb
+++ b/meta/recipes-support/libssh2/libssh2_1.11.1.bb
@@ -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"