Fortinet Patches CVE-2026-24858 After Active FortiOS SSO Exploitation Detected
Jan 28, 2026
Network Security / Zero-Day
Fortinet has begun releasing security updates to address a critical flaw impacting FortiOS that has come under active exploitation in the wild. The vulnerability, assigned the CVE identifier CVE-2026-24858 (CVSS score: 9.4), has been described as an authentication bypass related to FortiOS single sign-on (SSO). The flaw also affects FortiManager and FortiAnalyzer. The company said it's continuing to investigate if other products, including FortiWeb and FortiSwitch Manager, are impacted by the flaw. "An Authentication Bypass Using an Alternate Path or Channel vulnerability [CWE-288] in FortiOS, FortiManager, FortiAnalyzer may allow an attacker with a FortiCloud account and a registered device to log into other devices registered to other accounts, if FortiCloud SSO authentication is enabled on those devices," Fortinet said in an advisory released Tuesday. It's worth noting that the FortiCloud SSO login feature is not enabled in the default factory settings. It...
