CVE-2025-25255 Security feature bypass in FortiOS

What is CVE-2025-25255?

CVE-2025-25255 is a medium-severity vulnerability in Fortinet Fortios, published on 14 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An Improperly Implemented Security Check for Standard vulnerability [CWE-358] vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiProxy 7.6.0 through 7.6.3, FortiProxy 7.4.0 through 7.4.11, FortiProxy 7.2 all versions, FortiProxy 7.0.1 through 7.0.22 may allow an unauthenticated proxy user to bypass the domain fronting protection feature via crafted HTTP requests.

Weakness: CWE-358

Which versions are affected by CVE-2025-25255?

It affects 2 products.

Products include Fortinet Fortios, Fortinet Fortiproxy.

How do I fix CVE-2025-25255?

No fix has been published for CVE-2025-25255 yet. Limit exposure of the affected software until one is available.

Is CVE-2025-25255 being exploited?

There is no known exploitation of CVE-2025-25255 in the wild and no public exploit code.

Other vulnerabilities in Fortinet Fortios

• CVE-2024-23113 Fortinet Multiple Products Format String Exploited Critical 9.8
• CVE-2022-40684 Fortinet Multiple Products Authentication Bypass Exploited Critical 9.8
• CVE-2024-55591 Fortinet FortiOS and FortiProxy Authentication Bypass Exploited Critical 9.6
• CVE-2024-21762 Fortinet FortiOS Out-of-Bound Write Exploited Critical 9.6
• CVE-2022-42475 Fortinet FortiOS Heap-Based Buffer Overflow Exploited Critical 9.3

All Fortinet Fortios vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-mgv9-8jj6-qq93.