Format string error in FortiMail - CVE-2026-126163
Published: November 11, 2026
Vulnerability identifier: #VU165067
CSH Severity: High
CVSS v4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-126163
CWE-ID: CWE-134
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.
The vulnerability exists due to use of externally-controlled format string. A remote unauthenticated attacker can execute unauthorized code or commands via a specially crafted SMTP command.
Affected software
FortiMail
How to mitigate CVE-2026-126163
Install update from vendor's website.
FortiMail - update to 8.0.2