CVE-2025-59718

The vulnerability consists of improper verification of cryptographic signature (CWE-347) in the SAML response handled by FortiCloud SSO. An attacker without any credentials can send a crafted SAML response message whose signature is not properly validated by the vulnerable device. As a result, the system accepts the forged response as authentic and grants access, bypassing the entire authentication process.

An unauthenticated remote attacker gains full administrative access to Fortinet devices protected by FortiCloud SSO, which can lead to complete takeover of network infrastructure, including firewalls and proxies.

Apply patches available from the vendor according to references (https://fortiguard.fortinet.com/psirt/FG-IR-25-647). Until updates are deployed, it is recommended to monitor SSO logs for suspicious authentications and consider disabling FortiCloud SSO on publicly exposed devices.

FortiOS 7.6.0–7.6.3, FortiOS 7.4.0–7.4.8, FortiOS 7.2.0–7.2.11, FortiOS 7.0.0–7.0.17; FortiProxy 7.6.0–7.6.3, FortiProxy 7.4.0–7.4.10, FortiProxy 7.2.0–7.2.14, FortiProxy 7.0.0–7.0.21; FortiSwitchManager 7.2.0–7.2.6, FortiSwitchManager 7.0.0–7.0.5

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Fortinet FortiOS, FortiSwitchMaster, FortiProxy, and FortiWeb contain an improper verification of cryptographic signature vulnerability that may allow an unauthenticated attacker to bypass the FortiCloud SSO login authentication via a crafted SAML message. Please be aware that CVE-2025-59719 pertains to the same problem and is mentioned in the same vendor advisory. Ensure to apply all patches mentioned in the advisory.