Improper access control in OpenSSH - CVE-2026-59999
Published: July 15, 2026
Vulnerability identifier: #VU137701
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-59999
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: OpenSSH
Affected software:
OpenSSH
OpenSSH
Detailed vulnerability description
The vulnerability allows a remote user to enable tunneling despite forwarding restrictions.
The vulnerability exists due to improper access control in sshd(8) when DisableForwarding=yes and PermitTunnel=yes are configured together. A remote privileged user can use tunneling despite forwarding restrictions to enable tunneling despite forwarding restrictions.
Exploitation requires configurations where PermitTunnel is enabled.
How to mitigate CVE-2026-59999
Install security update from vendor's website.