Multiple Fortinet products are affected by a critical authentication bypass vulnerability that permits unauthorized account access via FortiCloud SSO.

This is an Authentication Bypass Using an Alternate Path or Channel (CWE-288) vulnerability. It allows an attacker who possesses a legitimate FortiCloud account and a registered device to authenticate to other devices registered to different accounts, provided FortiCloud SSO is enabled.

With a CVSS score of 9.8, this vulnerability represents a critical risk of unauthorized access to sensitive network management infrastructure. Exploitation could allow attackers to gain control over security appliances, access logs, or modify firewall policies, leading to severe data breaches or complete network compromise.

Immediate Action: Update all affected Fortinet devices to the latest patched firmware versions as specified in the official Fortinet security advisory.

Proactive Monitoring: Review access logs for suspicious login patterns originating from unexpected FortiCloud accounts and monitor for unauthorized changes to administrative settings.

Compensating Controls: If patching is delayed, consider disabling FortiCloud SSO authentication as a temporary measure to block the attack vector.

Public Exploit Available: No

This vulnerability poses a severe threat to organizational security due to the potential for cross-account unauthorized access. Organizations should treat this as a high-priority update and ensure all affected Fortinet infrastructure is updated immediately to mitigate the risk of compromise.