CVE-2026-126253 Auth bypass in FortiOS
Unauthenticated attackers can broadcast LSA via crafted requests to FortiOS, bypassing authentication; Fortinet firewall operators should care.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Harmful if only installed
- No
- Needs a specific call
- No
- Fix
- None listed
What is CVE-2026-126253?
CVE-2026-126253 is a critical authentication bypass vulnerability in Fortinet FortiOS, published on 11 Nov 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A authentication bypass by primary weakness vulnerability in Fortinet FortiOS 8.0.0 through 8.0.1, FortiOS 7.6.0 through 7.6.7, FortiOS 7.4.0 through 7.4.12, FortiOS 7.2.0 through 7.2.13 may allow an unauthenticated attacker to broadcast LSA via specially crafted request
Weakness: CWE-305
Which versions are affected by CVE-2026-126253?
An affected version is exposed as installed. No special setting or call is needed.
How do I fix CVE-2026-126253?
No fix has been published for CVE-2026-126253 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-126253 being exploited?
There is no known exploitation of CVE-2026-126253 in the wild and no public exploit code.
Sources
Also known as GHSA-j3f4-wmxp-qvcr.