CVE-2026-126259 Auth bypass in FortiOS
Unauthenticated attackers can send crafted HA packets to run commands as super admin on FortiOS with specific HA configurations.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Harmful if only installed
- No
- Needs a specific call
- No
- Fix
- None listed
What is CVE-2026-126259?
CVE-2026-126259 is a critical authentication bypass vulnerability in Fortinet FortiOS, published on 11 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A missing authentication for critical function vulnerability in Fortinet FortiOS 8.0.0, 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 with HA FGSP + standalone-config-sync, or autoscale to execute command as super admin via crafted HA packets.
Weakness: CWE-306
Which versions are affected by CVE-2026-126259?
Only installations with a non-default setting turned on are exposed.
How do I fix CVE-2026-126259?
No fix has been published for CVE-2026-126259 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-2026-126259 being exploited?
There is no known exploitation of CVE-2026-126259 in the wild and no public exploit code.
Sources
Also known as GHSA-f2f6-qwmc-g833.