FortiOS Single Sign-On Abuse: Incident Analysis and Guidance
🔒 Fortinet issued an advisory describing two FortiCloud SSO bypass vulnerabilities (CVE-2025-59718 and CVE-2025-59719) discovered during an internal code audit. The flaws allowed crafted SAML assertions to bypass authentication on FortiOS, FortiWeb, FortiProxy, and FortiSwitch Manager when FortiCloud SSO was enabled. Recent reports show active exploitation, including instances against fully patched devices, indicating a new attack path. Fortinet advises monitoring IOCs, restricting administrative access, disabling FortiCloud SSO as a workaround, and treating affected systems as compromised.
