# Fortinet FortiOS and FortiProxy: FortiOS and FortiProxy Authentication Bypass Vulnerability · pwn.watch

> 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. Added to CISA KEV on 2025-01-14.

Page: https://pwn.watch/i/fortinet-fortios-and-fortiproxy-cve-2024-55591 · generated 2026-10-22T21:47:37.879Z

## Status
- Severity: critical · status: closed · patch: patched
- Product: Fortinet FortiOS and FortiProxy
- Started: 2025-01-14 · closed: 2025-01-14
- CVEs: CVE-2024-55591
- Affected: See vendor advisory / CISA notes (versions not always listed in KEV feed)
- Fixed in: See vendor advisory linked in sources

## Follow this incident
- RSS (one item per update): https://pwn.watch/i/fortinet-fortios-and-fortiproxy-cve-2024-55591/feed.xml
- JSON Feed: https://pwn.watch/i/fortinet-fortios-and-fortiproxy-cve-2024-55591/feed.json
- Full data (timeline, sources, posts, agentBrief): https://pwn.watch/i/fortinet-fortios-and-fortiproxy-cve-2024-55591.json
- This file: https://pwn.watch/i/fortinet-fortios-and-fortiproxy-cve-2024-55591/llms.txt

## Updates (newest first)
- 2025-01-14: CISA added CVE-2024-55591 to the KEV catalog (due 2025-01-21).

## Fix brief
# Security brief: Fortinet FortiOS and FortiProxy: FortiOS and FortiProxy Authentication Bypass Vulnerability

Source: https://pwn.watch/i/fortinet-fortios-and-fortiproxy-cve-2024-55591 · status: closed (closed Jan 14, 2025) · severity: critical · updated Jan 14, 2025

## Patch status
**PATCHED: fixed releases exist. Upgrade to a fixed version.**

## 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. Added to CISA KEV on 2025-01-14.

Severity detail: CVSS 9.6 (CNA, v3.1); actively exploited (CISA KEV); known ransomware use

- Product: Fortinet FortiOS and FortiProxy
- CVE / advisory ids: CVE-2024-55591

## Affected versions
- See vendor advisory / CISA notes (versions not always listed in KEV feed)

## Check whether you're affected
No generic command applies (the product is a hosted service, appliance or desktop app). Check the installed version in its admin UI / About screen and compare with the versions above.

## Fix
Upgrade to one of these fixed versions (or later on the same branch):
- See vendor advisory linked in sources

After upgrading, re-run the checks above and redeploy/restart the affected services.

## Latest updates
- Jan 14, 2025: CISA added CVE-2024-55591 to the KEV catalog (due 2025-01-21).

## Advisories
- [Fortinet advisory: Fortinet FortiOS and FortiProxy](https://fortiguard.fortinet.com/psirt/FG-IR-24-535) (Fortinet)
- [NVD: CVE-2024-55591](https://nvd.nist.gov/vuln/detail/CVE-2024-55591) (NVD)
- [CISA Known Exploited Vulnerabilities Catalog](https://www.cisa.gov/known-exploited-vulnerabilities-catalog) (CISA)

## Caveats
Derived from CISA KEV JSON feed catalogVersion 2026.10.21. CVSS from the CVE record (cvelistV5). Exact affected/fixed version strings are not always in the KEV record; verify against the vendor advisory URL. startedAt uses dateAdded (exploitation may have begun earlier; many entries are older CVEs newly confirmed as exploited in 2025).

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Machine-readable: https://pwn.watch/i/fortinet-fortios-and-fortiproxy-cve-2024-55591.json · all incidents: https://pwn.watch/incidents.json. Verify against the vendor advisory before changing production systems.