Threat actors started to exploit two critical flaws (CVE: 2025-59718 and CVE: 2025-59719 in Fortinet FortiGate devices. Unauthenticated attackers can exploit these vulnerabilities to bypass SSO login protections using crafted SAML messages when FortiCloud SSO is enabled on affected devices.
December 12, 2025, Arctic Wolf identified coordinated attacks using malicious Single Sign-On (SSO) logins on FortiGate devices globally.
FortiOS 6.4, FortiWeb 7.0, and FortiWeb 7.2 remain unaffected by these vulnerabilities.
Source: Arcticwolf
Fortinet customers who identify related indicators of compromise (IoCs) should assume a breach and reset their hashed firewall credentials from the exposed configurations.
Workaround:
Fortinet recommends turning off the FortiCloud login feature (if enabled) temporarily until upgrading to a non-affected version.
To turn off FortiCloud login, go to System -> Settings -> Switch “Allow administrative login using FortiCloud SSO” to Off.