Improper access control in OpenSSH - CVE-2026-73283
Published: September 3, 2026
Vulnerability identifier: #VU146883
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-73283
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to bypass forwarding restrictions.
The vulnerability exists due to improper access control in sshd authorized_keys restrict keyword enforcement when handling tunnel forwarding. A remote user can use tunnel forwarding despite intended restrictions to bypass forwarding restrictions.
Tunnel forwarding is administratively disabled by default.
Affected software
OpenSSH
Ubuntu
openssh (Ubuntu package)
Ubuntu
openssh (Ubuntu package)
How to mitigate CVE-2026-73283
Install security update from vendor's website.
OpenSSH - update to 10.5p1
openssh (Ubuntu package) - addressed in versions 1:8.9p1-3ubuntu0.17, 1:9.6p1-3ubuntu13.19, 1:10.2p1-2ubuntu3.6
openssh (Ubuntu package) - addressed in versions 1:8.9p1-3ubuntu0.17, 1:9.6p1-3ubuntu13.19, 1:10.2p1-2ubuntu3.6