CVE-2021-42761: Fortinet FortiWeb

Critical severity, CVSS 9.8. EPSS: 1.5% chance of exploitation in the next 30 days.

A condition for session fixation vulnerability [CWE-384] in the session management of FortiWeb versions 6.4 all versions, 6.3.0 through 6.3.16, 6.2.0 through 6.2.6, 6.1.0 through 6.1.2, 6.0.0 through 6.0.7, 5.9.0 through 5.9.1 may allow a remote, unauthenticated attacker to infer the session identifier of other users and possibly usurp their session.

Affected products

• Fortinet FortiWeb: from 5.6.0, before 5.9.2 (fixed in 5.9.2); from 6.0.0, before 6.0.8 (fixed in 6.0.8); from 6.1.0, before 6.1.3 (fixed in 6.1.3); from 6.2.0, before 6.2.7 (fixed in 6.2.7); from 6.3.0, before 6.3.17 (fixed in 6.3.17); from 6.4.0, before 7.0.0 (fixed in 7.0.0)

Published 2023-02-16. Last modified 2026-06-17.