Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability
- Severity
- Critical9.8CVSS 3.1, Critical
- EPSS
- 68%
- Published
- 9 Dec 2025
- Updated
- 11 Aug 2026
Description
Title, description and vendor guidance are quoted from the source records.
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.
Weakness: CWE-347
Known exploited
Added to CISA KEV on 16 Dec 2025
Federal remediation due date: 23 Dec 2025
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.
Exploit prediction
68% probability of exploitation in the next 30 days (percentile 99%).
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
What the source states, per branch
Versions matched by Patcharo
Fortinet FortiOSSource: Fortinet (CVE record)
| Branch | Affected | Fixed in |
|---|---|---|
| 7.6 | 7.6.0 – 7.6.3 | Fixed after 7.6.3 |
| 7.4 | 7.4.0 – 7.4.8 | Fixed after 7.4.8 |
| 7.2 | 7.2.0 – 7.2.11 | Fixed after 7.2.11 |
| 7.0 | 7.0.0 – 7.0.17 | Fixed after 7.0.17 |
Versions not listed are stated unaffected by the vendor.
Fortinet FortiProxySource: Fortinet (CVE record)
| Branch | Affected | Fixed in |
|---|---|---|
| 7.6 | 7.6.0 – 7.6.3 | Fixed after 7.6.3 |
| 7.4 | 7.4.0 – 7.4.10 | Fixed after 7.4.10 |
| 7.2 | 7.2.0 – 7.2.14 | Fixed after 7.2.14 |
| 7.0 | 7.0.0 – 7.0.21 | Fixed after 7.0.21 |
Versions not listed are stated unaffected by the vendor.
Affected products
- Fortinet FortiSwitchManager · 7.2.0 ≤ 7.2.6, 7.0.0 ≤ 7.0.5
Workaround / Vendor remediation
Vendor remediation · FortiOS
Upgrade to FortiSwitchManager version 7.2.7 or above Upgrade to FortiSwitchManager version 7.0.6 or above Upgrade to FortiProxy version 7.6.4 or above Upgrade to FortiProxy version 7.4.11 or above Upgrade to FortiProxy version 7.2.15 or above Upgrade to FortiProxy version 7.0.22 or above Upgrade to FortiOS version 7.6.4 or above Upgrade to FortiOS version 7.4.9 or above Upgrade to FortiOS version 7.2.12 or above Upgrade to FortiOS version 7.0.18 or above Upgrade to FortiWeb version 8.0.1 or above Upgrade to FortiWeb version 7.6.5 or above Upgrade to FortiWeb version 7.4.10 or above Fortinet remediated this issue in FortiSASE version 25.3.b and hence customers do not need to perform any action. Upgrade to FortiPAM version 1.8.0 or above
Vendor remediation · FortiProxy
Upgrade to FortiSwitchManager version 7.2.7 or above Upgrade to FortiSwitchManager version 7.0.6 or above Upgrade to FortiProxy version 7.6.4 or above Upgrade to FortiProxy version 7.4.11 or above Upgrade to FortiProxy version 7.2.15 or above Upgrade to FortiProxy version 7.0.22 or above Upgrade to FortiOS version 7.6.4 or above Upgrade to FortiOS version 7.4.9 or above Upgrade to FortiOS version 7.2.12 or above Upgrade to FortiOS version 7.0.18 or above Upgrade to FortiWeb version 8.0.1 or above Upgrade to FortiWeb version 7.6.5 or above Upgrade to FortiWeb version 7.4.10 or above Fortinet remediated this issue in FortiSASE version 25.3.b and hence customers do not need to perform any action. Upgrade to FortiPAM version 1.8.0 or above
References
- https://fortiguard.fortinet.com/psirt/FG-IR-25-647(opens in a new tab)
- https://arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719/(opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-864900.html(opens in a new tab)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59718(opens in a new tab)
Provenance
Every fact on this page comes from the sources below. Nothing is written by an AI.
- Fortinet (CVE record)
- Fortinet (CVE record) · 27 Sept 2026, 23:46 UTC · Parser patcharo-cve5/1.1.0
- CISA Known Exploited Vulnerabilities
- CISA Known Exploited Vulnerabilities · 27 Sept 2026, 23:42 UTC · Parser patcharo-kev/1.0.0
- NVD
- NVD · 27 Sept 2026, 23:44 UTC · Parser patcharo-nvd/1.0.0
- FIRST EPSS
- FIRST EPSS · 27 Sept 2026, 23:46 UTC · Parser patcharo-epss/1.0.0
Last verified: 28 Sept 2026, 02:31 UTC