Patched Fortinet Firewalls Breached in 2026: Authentication Bypass Exposes Enterprise Networks
In January 2026, patched FortiGate firewalls running FortiOS versions 7.4.9 and 7.4.10 were actively breached due to exploitation of a lingering authentication bypass flaw (CVE-2025-59718) in the FortiCloud SSO login feature. Despite an earlier patch, attackers utilized crafted SAML messages to create rogue admin accounts on exposed devices, as observed in customer logs and confirmed by Fortinet developers. More than 11,000 Internet-facing Fortinet devices remained vulnerable as attackers leveraged the flaw to gain privileged access and potentially compromise network defenses, triggering urgent remediation efforts. This incident underscores persisting risks from incomplete remediation, especially on security appliances pivotal to organizational defenses. Growing attacker expertise in exploiting authentication logic flaws and a surge in identity-based attacks highlight the necessity for ongoing vigilance, layered compensating controls, and rapid vulnerability response strategies.
Kill Chain