Known exploited · Fortinet
CVE-2024-55591: Fortinet FortiOS and FortiProxy Authentication Bypass Vulnerability
What it is
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.
- Vendor
- Fortinet
- Product
- FortiOS and FortiProxy
- Added to KEV
- January 14, 2025
- CISA due date
- January 21, 2025
- Ransomware use
- Known
What CISA requires
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Forensic triage
No
What to do now
- Find every instance of FortiOS and FortiProxy you run, including the forgotten ones, and check its version against the vendor advisory.
- Apply the vendor's fix or mitigation, before January 21, 2025 if you are bound by CISA's deadline, sooner if it faces the internet.
- Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
References
H2 Security
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Train the engineers who fix it
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Start freeSource: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.