CVE-2025-59718—Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability

Vulnerability Name

Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability

Description

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.

Known To Be Used in Ransomware Campaigns?

Ransomware Status:

Unknown

Action

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

Additional Notes

• https://fortiguard.fortinet.com/psirt/FG-IR-25-647
• https://docs.fortinet.com/upgrade-tool/fortigate
• https://nvd.nist.gov/vuln/detail/CVE-2025-59718

Related News Articles

• FortiGate Devices Exploited to Breach Networks and Steal Service Account CredentialsMarch 10, 2026
• Fortinet starts patching exploited FortiCloud SSO zero-day (CVE-2026-24858)January 28, 2026
• Fortinet blocks exploited FortiCloud SSO zero day until patch is readyJanuary 27, 2026
• Fortinet Confirms Active FortiCloud SSO Bypass on Fully Patched FortiGate FirewallsJanuary 23, 2026
• Fortinet confirms critical FortiCloud auth bypass not fully patchedJanuary 23, 2026

Related Weaknesses

• CWE-347