known ransomware use

Fortinet FortiOS and FortiProxy Authentication Bypass Vulnerability

Added to KEV
2025-01-14
Federal due date
2025-01-21
Vendor
Fortinet
Product
FortiOS and FortiProxy
EPSS
99.9th percentile (score 0.941, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Known
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2024-55591

CISA short description

Fortinet FortiOS and FortiProxy contain an authentication bypass vulnerability that may allow an unauthenticated, remote attacker to gain super-admin privileges via crafted requests to Node.js websocket module.

Required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.