Improper validation of certificate with host mismatch in FortiOS and FortiProxy - CVE-2025-25253
Published: October 15, 2025
Vulnerability identifier: #VU117216
CSH Severity: Medium
CVSS v4: 7.7 [CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2025-25253
CWE-ID: CWE-297
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.
The vulnerability exists due to improper validation of certificate with host mismatch. An unauthenticated attacker in a man-in-the middle position can intercept and tamper with connections to the ZTNA proxy.
Affected software
FortiOS
FortiProxy
FortiProxy
How to mitigate CVE-2025-25253
Install update from vendor's website.
FortiOS - addressed in versions 7.4.9, 7.6.3
FortiProxy - addressed in versions 7.4.9, 7.6.2
FortiProxy - addressed in versions 7.4.9, 7.6.2