CVE-2026-126239 Memory corruption in FortiAuthenticator
Unauthenticated attackers can crash the FortiAuthenticator FSSO subsystem with crafted HTTP requests; Fortinet customers should care.
- 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-2026-126239?
CVE-2026-126239 is a high-severity memory corruption vulnerability in Fortinet FortiAuthenticator, 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 stack-based buffer overflow vulnerability in Fortinet FortiAuthenticator 8.0.0 through 8.0.3, FortiAuthenticator 6.6.0 through 6.6.10 may allow an unauthenticated attacker to crash the FSSO subsystem via crafted http requests
Weakness: CWE-121
Which versions are affected by CVE-2026-126239?
An affected version is exposed as installed. No special setting or call is needed.
How do I fix CVE-2026-126239?
No fix has been published for CVE-2026-126239 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-126239 being exploited?
There is no known exploitation of CVE-2026-126239 in the wild and no public exploit code.
Sources
Also known as GHSA-v6gq-6xjh-32cg.