JWT used for authentication in web GUI signed with static key
Fortinet warns that FortiMonitorOnSight's web GUI uses JWTs signed with a static key, enabling remote unauthenticated authentication bypass.
Fortinet advisory FG-IR-26-170 discloses a CVSS 9.6 vulnerability (CWE-540, sensitive information in source code) in the FortiMonitorOnSight web portal. The web GUI's JWT authentication tokens are signed with a static key, allowing a remote unauthenticated attacker to bypass authentication via forged or reused JWTs. The advisory was revised on September 8, 2026.