CVEs / CVE-2025-59718
CVE-2025-59718: Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability
- Known exploited in the CISA KEV catalog since 16 Dec 2025
- critical 9.8 CVSS 3.1 (from the CNA)
- EPSS 68.2% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
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.
Description
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Fortinet FortiSwitchManager | from 7.2.0, up to and including 7.2.6 | — |
| Fortinet FortiSwitchManager | from 7.0.0, up to and including 7.0.5 | — |
| Fortinet FortiOS | from 7.6.0, up to and including 7.6.3 | — |
| Fortinet FortiOS | from 7.4.0, up to and including 7.4.8 | — |
| Fortinet FortiOS | from 7.2.0, up to and including 7.2.11 | — |
| Fortinet FortiOS | from 7.0.0, up to and including 7.0.17 | — |
| Fortinet FortiProxy | from 7.6.0, up to and including 7.6.3 | — |
| Fortinet FortiProxy | from 7.4.0, up to and including 7.4.10 | — |
| Fortinet FortiProxy | from 7.2.0, up to and including 7.2.14 | — |
| Fortinet FortiProxy | from 7.0.0, up to and including 7.0.21 | — |
| Siemens RUGGEDCOM APE1808 | all versions | — |
Exploitation
| In CISA KEV since | 16 Dec 2025 |
|---|---|
| Due date for US federal agencies | 23 Dec 2025 |
| Used in ransomware campaigns | Unknown |
| 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. |
Severity
| CVSS 3.1 | 9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-347 |
References
- CVE-2025-59718 on NVD
- CVE-2025-59718 in the CISA KEV catalog
- https://fortiguard.fortinet.com/psirt/FG-IR-25-647 (cited by CISA)
- https://docs.fortinet.com/upgrade-tool/fortigate (cited by CISA)
- https://fortiguard.fortinet.com/psirt/FG-IR-25-647 Vendor Advisory
- https://arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719/ Third Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-864900.html Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59718 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.