CVE-2026-126254 Integer overflow in FortiOS
A configured ibgp neighbor can send malformed attributes to all connected FortiOS routers via crafted requests.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- 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-2026-126254?
CVE-2026-126254 is a critical integer overflow vulnerability in Fortinet FortiOS, published on 11 Nov 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A numeric truncation error 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 a configured ibgp neighbor to send malicious/malformed attributes to all connected routers via a specially crafted request
Weakness: CWE-197
Which versions are affected by CVE-2026-126254?
Only installations with a non-default setting turned on are exposed.
How do I fix CVE-2026-126254?
No fix has been published for CVE-2026-126254 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Check arithmetic on sizes and lengths before using the result. More about Integer overflow.
Is CVE-2026-126254 being exploited?
There is no known exploitation of CVE-2026-126254 in the wild and no public exploit code.
Sources
Also known as GHSA-g2g3-rvm3-h345.