CVE-2026-126163 Memory corruption in FortiMail
Remote unauthenticated attackers can execute code on FortiMail via a crafted SMTP command exploiting a format string flaw.
- 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-2026-126163?
CVE-2026-126163 is a high-severity memory corruption vulnerability in Fortinet FortiMail, 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 use of externally-controlled format string vulnerability in Fortinet FortiMail 8.0.0 through 8.0.1 may allow a remote unauthenticated attacker to execute unauthorized code or commands via a specially crafted SMTP command.
Weakness: CWE-134
Which versions are affected by CVE-2026-126163?
An affected version is exposed as installed. No special setting or call is needed.
How do I fix CVE-2026-126163?
No fix has been published for CVE-2026-126163 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-2026-126163 being exploited?
There is no known exploitation of CVE-2026-126163 in the wild and no public exploit code.
Sources
Also known as GHSA-rcpr-f85j-6pq7.