CVE-2026-26035

Fortinet Patches Critical Authentication Bypass in FortiWeb Allowing Login with Random Credentials

Fortinet has released security updates addressing multiple vulnerabilities across FortiWeb, FortiManager, and FortiClient products. The most severe issue, tracked as CVE-2026-26035, affects FortiWeb and carries a CVSS score of 8.8. The flaw occurs when administrative accounts configured with remote RADIUS authentication use the wildcard option, which is disabled by default. Under these conditions, an unauthenticated remote attacker can gain administrative access to the web application firewall by supplying arbitrary usernames and passwords. Successful exploitation grants full control over the FortiWeb instance, potentially compromising web application security. The vulnerability impacts FortiWeb versions 8.0, 7.6, 7.4, 7.2, and 7.0, with fixes available in versions 8.0.3, 7.6.7, 7.4.12, and 7.2.13. No active exploitation of the authentication bypass flaws has been observed so far, but the risk of remote administrative access makes immediate patching essential for exposed appliances.