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[scarthgap,3/3] openssh: fix CVE-2026-73281

Message ID 20260930060027.1560262-3-hthakar@cisco.com
State Under Review
Delegated to: Yoann Congal
Headers show
Series [scarthgap,1/3] openssh: fix CVE-2026-73283 | expand

Commit Message

Hetvi Thakar -X (hthakar - E INFOCHIPS PRIVATE LIMITED at Cisco) Sept. 30, 2026, 6 a.m. UTC 
From: Hetvi Thakar <hthakar@cisco.com>

This patch applies the upstream fix that permits session-bind requests
while the agent is locked so forwarded sessions remain classified as
remote. 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/6a57081dc35acf3ee298108d4bc3580489608d5
[2] https://www.cve.org/CVERecord?id=CVE-2026-73281

Signed-off-by: Hetvi Thakar <hthakar@cisco.com>
---
 .../openssh/openssh/CVE-2026-73281.patch      | 76 +++++++++++++++++++
 .../openssh/openssh_9.6p1.bb                  |  1 +
 2 files changed, 77 insertions(+)
 create mode 100644 meta/recipes-connectivity/openssh/openssh/CVE-2026-73281.patch
diff mbox series

Patch

diff --git a/meta/recipes-connectivity/openssh/openssh/CVE-2026-73281.patch b/meta/recipes-connectivity/openssh/openssh/CVE-2026-73281.patch
new file mode 100644
index 0000000000..9f017ece17
--- /dev/null
+++ b/meta/recipes-connectivity/openssh/openssh/CVE-2026-73281.patch
@@ -0,0 +1,76 @@ 
+From df8fe9ebecc57c486f2d1ea5b1a5c34b22858bcb Mon Sep 17 00:00:00 2001
+From: "djm@openbsd.org" <djm@openbsd.org>
+Date: Fri, 7 Aug 2026 05:18:05 +0000
+Subject: [PATCH] upstream: Allow session-bind@openssh.com requests when the
+ agent is
+
+locked, otherwise forwarding sessions established with an agent was locked
+will be treated as local, rather than remote.
+
+Reported by sn0x-sharma
+
+OpenBSD-Commit-ID: 524f210c6f2b3a06e0a2f6d0af5188a9a75fa2c7
+
+CVE: CVE-2026-73281
+Upstream-Status: Backport [https://github.com/openssh/openssh-portable/commit/6a57081dc35acf3ee298108d4bc3580489608d5f]
+
+Backport Changes:
+- Omitted the upstream OpenBSD RCS revision header update because it does
+  not apply to the OpenSSH 9.6p1 source revision.
+- OpenSSH 9.6p1 lacks the later query extension and replied/generic_fail
+  dispatch, so locked non-session-bind extensions retain the 9.6p1
+  success=false response path.
+
+(cherry picked from commit 6a57081dc35acf3ee298108d4bc3580489608d5f)
+Signed-off-by: Hetvi Thakar <hthakar@cisco.com>
+---
+ ssh-agent.c | 18 +++++++++++++++---
+ 1 file changed, 15 insertions(+), 3 deletions(-)
+
+diff --git a/ssh-agent.c b/ssh-agent.c
+index 2d2c6fcc..f1c35fd2 100644
+--- a/ssh-agent.c
++++ b/ssh-agent.c
+@@ -1778,10 +1778,19 @@ process_extension(SocketEntry *e)
+ 		error_fr(r, "parse");
+ 		goto send;
+ 	}
+-	if (strcmp(name, "session-bind@openssh.com") == 0)
++	/*
++	 * This function can be called while the agent is locked to allow
++	 * session binds to be processed for new channels.
++	 * Other operations should be refused when locked.
++	 */
++
++	if (strcmp(name, "session-bind@openssh.com") == 0) {
+ 		success = process_ext_session_bind(e);
+-	else
++	} else if (locked) {
++		debug_f("attempt to use extension \"%s\" while locked", name);
++	} else {
+ 		debug_f("unsupported extension \"%s\"", name);
++	}
+ 	free(name);
+ send:
+ 	send_status(e, success);
+@@ -1831,16 +1840,19 @@ process_message(u_int socknum)
+ 
+ 	/* check whether agent is locked */
+ 	if (locked && type != SSH_AGENTC_UNLOCK) {
+-		sshbuf_reset(e->request);
+ 		switch (type) {
+ 		case SSH2_AGENTC_REQUEST_IDENTITIES:
+ 			/* send empty lists */
+ 			no_identities(e);
+ 			break;
++		case SSH_AGENTC_EXTENSION:
++			process_extension(e);
++			break;
+ 		default:
+ 			/* send a fail message for all other request types */
+ 			send_status(e, 0);
+ 		}
++		sshbuf_reset(e->request);
+ 		return 1;
+ 	}
+ 
diff --git a/meta/recipes-connectivity/openssh/openssh_9.6p1.bb b/meta/recipes-connectivity/openssh/openssh_9.6p1.bb
index 651b7437a6..572a614380 100644
--- a/meta/recipes-connectivity/openssh/openssh_9.6p1.bb
+++ b/meta/recipes-connectivity/openssh/openssh_9.6p1.bb
@@ -46,6 +46,7 @@  SRC_URI = "http://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-${PV}.tar
            file://CVE-2026-60000.patch \
            file://CVE-2026-73283.patch \
            file://CVE-2026-73282.patch \
+           file://CVE-2026-73281.patch \
            "
 SRC_URI[sha256sum] = "910211c07255a8c5ad654391b40ee59800710dd8119dd5362de09385aa7a777c"