CVE-2025-59718FortinetFirewall and VPNDecember 16, 2025

Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability

Critical 9.8Actively exploited

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.

What to do

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

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Details

Vendor
Fortinet
Product
FortiOS
CVE
CVE-2025-59718
Affected versions
FortiSwitchManager 7.2: from 7.2.0 to 7.2.6
FortiSwitchManager 7.0: from 7.0.0 to 7.0.5
FortiOS 7.6: from 7.6.0 to 7.6.3
FortiOS 7.4: from 7.4.0 to 7.4.8
FortiOS 7.2: from 7.2.0 to 7.2.11
FortiOS 7.0: from 7.0.0 to 7.0.17
FortiProxy 7.6: from 7.6.0 to 7.6.3
FortiProxy 7.4: from 7.4.0 to 7.4.10
FortiProxy 7.2: from 7.2.0 to 7.2.14
FortiProxy 7.0: from 7.0.0 to 7.0.21 (from the advisory and NVD; check the exact builds in the official advisory)
CVSS score
9.8
Actively exploited
Yes, listed in the CISA Known Exploited Vulnerabilities catalog
CISA due date
December 23, 2025 (deadline for US federal agencies: a good benchmark for you too)
Source
CISA KEV – original advisory
Published
December 16, 2025

The description and the recommended action are quoted from the public advisory; severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.

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