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

CVE-2025-59718 (Fortinet Multiple Products) is in the CISA Known Exploited Vulnerabilities catalog since 2025-12-16. Fortinet FortiOS, FortiSwitchMaster, FortiProxy, and FortiWeb contain an improper verification of… See the required fix, due date and advisories.

Exploitation status

CVE-2025-59718 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 2025-12-16. 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.

Advisory facts

Vendor or project
Fortinet
Affected product
Multiple Products
Added to CISA KEV
2025-12-16
US federal remediation due date
2025-12-23
Ransomware association
Unknown
EPSS score
63.5% chance of exploitation in 30 days
Weakness (CWE)
CWE-347

Remediation: the 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.

Wording published by CISA for this catalog entry. It is the baseline action, not a decision about your environment: whether this exposure matters for you depends on where the affected component runs, what it is exposed to and who owns it.

From advisory to a decision you can defend

A catalog entry tells you a vulnerability is being exploited somewhere. It does not tell you whether it matters in your estate, who owns the fix, or what evidence an auditor will ask for later. That is the work VulnTrek does: it takes findings from the tools you already run, decides which exposure actually matters, routes it to an owner, keeps remediation human-approved and retains the lineage as evidence.

Sourced from public upstream advisories (CISA KEV, ENISA EUVD, vendor PSIRTs) mirrored daily. Informational only — not a remediation decision, not legal advice, and the absence of a record is not evidence of safety.