CVE-2025-59718
Improper Verification of Cryptographic Signature in Fortinet Multiple Products. CISA confirmed attackers exploit it and added it to its Known Exploited Vulnerabilities catalog on 16 December 2025.
- Product
- Fortinet Multiple Products
- Added to CISA's catalog
- Federal fix-by date
- Ransomware
- No known use in ransomware campaigns
- Sources
- CISA’s catalog, NVD entry
CISA’s 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.
More from Fortinet this year.
- CVE-2025-61624 Path Traversal, added
- CVE-2026-104286 Path Traversal, added
- CVE-2025-25249 Heap-based Buffer Overflow, added
- CVE-2025-68686 Exposure of Sensitive Information to an Unauthorized Actor, added
- CVE-2026-39808 OS Command Injection, added
- CVE-2026-25089 OS Command Injection, added
- CVE-2026-21643 SQL Injection, added
- CVE-2026-35616 Improper Access Control, added
Every flaw CISA confirmed exploited in the last 30 days is on the exploit watch. This is not security advice. Check the vendor’s advisory before acting. From CISA’s catalog of 30 October 2026.