CVE-2025-31366: Fortinet FortiOS

Medium severity, CVSS 6.1. EPSS: 0.4% chance of exploitation in the next 30 days.

An Improper Neutralization of Input During Web Page Generation vulnerability [CWE-79] vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4 all versions, FortiProxy 7.6.0 through 7.6.3, FortiProxy 7.4 all versions, FortiProxy 7.2 all versions, FortiProxy 7.0 all versions, FortiSASE 25.2.a may allow an unauthenticated attacker to perform a reflected cross site scripting (XSS) via crafted HTTP requests.

Affected products

• Fortinet FortiOS: from 6.4.0, before 7.4.9 (fixed in 7.4.9); from 7.6.0, before 7.6.4 (fixed in 7.6.4)
• Fortinet FortiProxy: from 7.0.0, before 7.6.4 (fixed in 7.6.4)
• Fortinet Fortisase: version 25.3.40 only

Published 2025-10-14. Last modified 2026-07-08.