Known exploited vulnerability
CVE-2025-59718
The short answer
CVE-2025-59718 affects Fortinet FortiSwitchManager and is rated critical (CVSS 9.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2025-12-16: attackers are using it, so patch it first.
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.
Weakness: CWE-347.
Severity
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploited (CISA KEV)
Yes, since Dec 16, 2025
Federal due date Dec 23, 2025
EPSS, next 30 days
68%
Higher than 99% of scored CVEs
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
What CISA says 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.
Affected products
FortiSwitchManager, FortiOS, FortiProxy, RUGGEDCOM APE1808. NVD's record lists the exact affected versions.
References
- fortiguard.fortinet.com/psirt/FG-IR-25-647 Vendor Advisory
- arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719/ Third Party Advisory
- cert-portal.siemens.com/productcert/html/ssa-864900.html Third Party Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59718 US Government Resource
Questions
Is CVE-2025-59718 being exploited?
Yes. CISA added CVE-2025-59718 to its Known Exploited Vulnerabilities catalog on 2025-12-16, with a federal remediation due date of 2025-12-23.
How do I fix CVE-2025-59718?
CISA's 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.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.
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