# CVE-2025-59718

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.

- Page: https://www.vulneraibility.com/cve/CVE-2025-59718
- CVSS: 9.8
- Known exploited: yes, in CISA KEV since 2025-12-16; CISA due date 2025-12-23
- EPSS: 68.29%
- Unvetted proof-of-concept code on GitHub: 2 GitHub proofs of concept (first 2025-12-17)
- CISA SSVC: exploitation active, automatable yes, technical impact total (assessed 2025-12-17)
- Weakness: CWE-347
- Published: 2025-12-09

## Affected versions

- Fortinet FortiOS: affected >= 7.6.0 and <= 7.6.3; >= 7.4.0 and <= 7.4.8; >= 7.2.0 and <= 7.2.11; >= 7.0.0 and <= 7.0.17
- Fortinet FortiProxy: affected >= 7.6.0 and <= 7.6.3; >= 7.4.0 and <= 7.4.10; >= 7.2.0 and <= 7.2.14; >= 7.0.0 and <= 7.0.21
- Fortinet FortiSwitchManager: affected >= 7.2.0 and <= 7.2.6; >= 7.0.0 and <= 7.0.5

A version outside these ranges is not a statement that it is unaffected.

## References

- [other] https://fortiguard.fortinet.com/psirt/FG-IR-25-647
- [advisory] https://arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719/
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59718
- [other] https://cert-portal.siemens.com/productcert/html/ssa-864900.html

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.