openssh: Fix CVE-2026-59996

This patch applies the upstream OpenSSH 10.4 backport for
CVE-2026-59996. The upstream fix commit is referenced in [1],
and the public CVE advisory is referenced in [2].

[1] https://github.com/openssh/openssh-portable/commit/36480181fa22f98e180b4f9e10203480c0346c78
[2] https://nvd.nist.gov/vuln/detail/CVE-2026-59996

(From OE-Core rev: c0c407666d264d94091d994f2d468369c37cc336)

Signed-off-by: Devansh Patel <devanshp@cisco.com>
Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Signed-off-by: Paul Barker <paul@pbarker.dev>

meta/recipes-connectivity/openssh/openssh/CVE-2026-59996.patch

@@ -0,0 +1,37 @@
+From 762b3d438547893d62ce3e147dce6cef14697b09 Mon Sep 17 00:00:00 2001
+From: "djm@openbsd.org" <djm@openbsd.org>
+Date: Sun, 28 Jun 2026 23:47:16 +0000
+Subject: [PATCH] upstream: resist that return ".." via remote glob during
+
+remote/remote copies, similar to fixes for bz3871 for remote/local copies.
+From Swival scanner
+
+CVE: CVE-2026-59996
+Upstream-Status: Backport [https://github.com/openssh/openssh-portable/commit/36480181fa22f98e180b4f9e10203480c0346c78]
+
+Backport Changes:
+- Retained the Scarthgap scp.c OpenBSD revision identifier because the
+  10.4 identifier does not describe the older source baseline.
+
+OpenBSD-Commit-ID: c0c20a1b746db55c08e53658bf21ea9405b300a5
+(cherry picked from commit 36480181fa22f98e180b4f9e10203480c0346c78)
+Signed-off-by: Devansh Patel <devanshp@cisco.com>
+---
+ scp.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/scp.c b/scp.c
+index 2c21fa19a..00d87517d 100644
+--- a/scp.c
++++ b/scp.c
+@@ -2043,6 +2043,10 @@ throughlocal_sftp(struct sftp_conn *from, struct sftp_conn *to,
+ 			goto out;
+ 		}
+ 
++		/* Special handling for source of '..' */
++		if (strcmp(filename, "..") == 0)
++			filename = "."; /* Download to dest, not dest/.. */
++
+ 		if (targetisdir)
+ 			abs_dst = sftp_path_append(target, filename);
+ 		else

meta/recipes-connectivity/openssh/openssh_9.6p1.bb

@@ -39,6 +39,7 @@ SRC_URI = "http://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-${PV}.tar
            file://CVE-2026-35388.patch \
            file://CVE-2026-59999.patch \
            file://CVE-2026-59997.patch \
+           file://CVE-2026-59996.patch \
            "
 SRC_URI[sha256sum] = "910211c07255a8c5ad654391b40ee59800710dd8119dd5362de09385aa7a777c"