CVE-2026-126237 Denial of service in FortiAuthenticator
Crafted TCP requests can trigger an infinite loop in FortiAuthenticator, causing denial of service.
- 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-2026-126237?
CVE-2026-126237 is a high-severity denial of service 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 loop with unreachable exit condition ('infinite loop') vulnerability in Fortinet FortiAuthenticator 8.0.0 through 8.0.3, FortiAuthenticator 6.6.0 through 6.6.10 may allow an attacker to cause a denial of service via crafted TCP requests.
Weakness: CWE-835
Which versions are affected by CVE-2026-126237?
An affected version is exposed as installed. No special setting or call is needed.
How do I fix CVE-2026-126237?
No fix has been published for CVE-2026-126237 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-126237 being exploited?
There is no known exploitation of CVE-2026-126237 in the wild and no public exploit code.
Sources
Also known as GHSA-8fpc-w23q-m5g7.