Improper verification of cryptographic signature in Fortinet, Inc products - CVE-2025-59718
Published: December 10, 2025 / Updated: January 9, 2026
Vulnerability identifier: #VU119694
CSH Severity: Critical
CVSS v4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2025-59718
CWE-ID: CWE-347
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vulnerability details
The vulnerability allows a remote attacker to bypass SSO authentication.
The vulnerability exists due to improper verification of cryptographic signature when handling SAML messages. A remote non-authenticated attacker can bypass the FortiCloud SSO login authentication via a crafted SAML message.
Successful exploitation of the vulnerability requires that the FortiCloud SSO feature is enabled on the device. However, when an administrator registers the device to FortiCare from the device's GUI, unless the administrator disables the toggle switch "Allow administrative login using FortiCloud SSO" in the registration page, FortiCloud SSO login is enabled upon registration.
Affected software
FortiProxy
FortiOS
FortiSwitch Manager
FortiWeb
FortiOS
FortiSwitch Manager
FortiWeb
How to mitigate CVE-2025-59718
Install updates from vendor's website.
FortiProxy - addressed in versions 7.0.22, 7.2.15, 7.4.11, 7.6.4
FortiOS - addressed in versions 7.0.18, 7.2.12, 7.4.9, 7.6.4
FortiSwitch Manager - addressed in versions 7.0.6, 7.2.7
FortiWeb - addressed in versions 7.4.10, 7.6.5, 8.0.1
FortiOS - addressed in versions 7.0.18, 7.2.12, 7.4.9, 7.6.4
FortiSwitch Manager - addressed in versions 7.0.6, 7.2.7
FortiWeb - addressed in versions 7.4.10, 7.6.5, 8.0.1