Re: [wrynose] [PATCH] libssh2: fix CVE-2026-55199

["Yoann Congal" <yoann.congal@smile.fr>]

On Mon Jun 29, 2026 at 10:19 AM CEST, daniel.turull wrote:
> 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
Hello

The Reviewed-by: line is missing a '>' at the end.
I've fixed it.

Regards,

> 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 5ffc40b8fc..2407ed34d9 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"


-- 
Yoann Congal
Smile ECS