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.
Conclusion & alert: CVE-2025-59718 is rated Critical Active Threat (98/100): CVSS Critical severity, with high exploitation likelihood (EPSS 9.49%, 93th percentile). Core evidence: CISA KEV confirms active exploitation (added 2025-12-16) affecting Fortinet / Multiple Products. a weakness (CWE-347) Unauthenticated remote administrative access may be possible. EPSS rose +1.30% over the last day, indicating growing attacker interest. Mandatory action: The CISA remediation deadline has passed—treat as an emergency patch priority.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
: Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability · CISA KEV detail
: 2025-12-16
: 2025-12-23
: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-25 | 8.18% | 9.49% | +1.30% |
| 2 | 2026-05-12 | 10.73% | 8.18% | -2.55% |
| 3 | 2026-05-09 | — | 10.73% | — |
Full EPSS history (28 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| fortinet | fortiproxy | >= 7.0.0, < 7.0.22 | cpe:2.3:a:fortinet:fortiproxy:*:*:*:*:*:*:*:* |
| fortinet | fortiproxy | >= 7.2.0, < 7.2.15 | cpe:2.3:a:fortinet:fortiproxy:*:*:*:*:*:*:*:* |
| fortinet | fortiproxy | >= 7.4.0, < 7.4.11 | cpe:2.3:a:fortinet:fortiproxy:*:*:*:*:*:*:*:* |
| fortinet | fortiproxy | >= 7.6.0, < 7.6.4 | cpe:2.3:a:fortinet:fortiproxy:*:*:*:*:*:*:*:* |
| fortinet | fortiswitchmanager | >= 7.0.0, < 7.0.6 | cpe:2.3:a:fortinet:fortiswitchmanager:*:*:*:*:*:*:*:* |
| fortinet | fortiswitchmanager | >= 7.2.0, < 7.2.7 | cpe:2.3:a:fortinet:fortiswitchmanager:*:*:*:*:*:*:*:* |
| fortinet | fortios | >= 7.0.0, < 7.0.18 | cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:* |
| fortinet | fortios | >= 7.2.0, < 7.2.12 | cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:* |
| fortinet | fortios | >= 7.4.0, < 7.4.9 | cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:* |
| fortinet | fortios | >= 7.6.0, < 7.6.4 | cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| 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://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59718 | US Government Resource |