Actively exploited
Listed in CISA’s Known Exploited Vulnerabilities catalog since December 16, 2025.
CVE-2025-59718
Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability
Added to KEV December 16, 2025
Alert details
- Source feed
- CISA KEV
- CVE ID
- CVE-2025-59718
- CWE
- CWE-347
- Affected products
- Multiple Products · Fortinet Multiple Products · Fortinet
What happened
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.
What it means for your business
Fortinet Multiple Products is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2025-59718). 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. CISA remediation due date: 2025-12-23. If you need help checking exposure, call (864) 335-9223.
Required 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.
CISA due date: December 23, 2025
Sources
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