Fortinet · Multiple Products
CVE-2025-59718
Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability
What it is
A improper verification of cryptographic signature vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2.0 through 7.2.11, FortiOS 7.0.0 through 7.0.17, FortiProxy 7.6.0 through 7.6.3, FortiProxy 7.4.0 through 7.4.10, FortiProxy 7.2.0 through 7.2.14, FortiProxy 7.0.0 through 7.0.21, FortiSwitchManager 7.2.0 through 7.2.6, FortiSwitchManager 7.0.0 through 7.0.5 allows an unauthenticated attacker to bypass the FortiCloud SSO login authentication via a crafted SAML response message.
CISA: 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.
Deadline for US federal agencies: December 23, 2025
- Added to the CISA list
- December 16, 2025
- Published
- December 9, 2025
- Severity
- Critical 9.1 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 68% in the top 0.7% of all known vulnerabilities
- Weakness
- CWE-347
- More details
- NVD · CVE.org · CISA
All references (1)
More exploited flaws from Fortinet
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Oct 16, 2026 | Path Traversal | Multiple Products | Medium 5.4 | 1.3% |
| Sep 9, 2026 | Heap-based Buffer Overflow | Multiple Products | High 7.4 | 3.7% |
| Jan 27, 2026 | Authentication Bypass Using an Alternate Path or Channel | Multiple Products | Critical 9.4 | 87% |
| May 14, 2025 | Stack-Based Buffer Overflow | Multiple Products | Critical 9.6 | 31% |
| Oct 9, 2024 | Format String | Multiple Products | Critical 9.8 | 62% |
| Oct 11, 2022 | Authentication Bypass | Multiple Products | Critical 9.8 | >99.9% |
| Oct 1, 2026 | Path Traversal | FortiMail | Critical 9.8 | 4.6% |
| Jul 27, 2026 | Exposure of Sensitive Information to an Unauthorized Actor | FortiOS | Medium 5.3 | 29% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.