Exploited CVEs / Fortinet / CVE-2024-55591
CVE-2024-55591
Fortinet FortiOS and FortiProxy Authentication Bypass Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted, and the vulnerability is known to be used in ransomware campaigns. Federal agencies were required to remediate by 2025-01-21 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Fortinet PSIRT Advisories, linked below.
Actively exploited Fortinet FortiOS and FortiProxy vulnerability, Critical severity, CVSS 9.8. Added to the CISA KEV catalog 2025-01-14.
Risk summary
Updated July 26, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2024-55591
Ransomware operators are using this Fortinet flaw to become super-admin on FortiOS and FortiProxy devices: crafted requests to the Node.js websocket module bypass authentication entirely. It scores 98% on EPSS, carries a Critical CVSS 9.8 rating, and was KEV-listed on 2025-01-14. Super-admin on a perimeter firewall means the attacker controls the security boundary itself, including VPN configuration and traffic policy.
Do this: Upgrade FortiOS and FortiProxy now, disable internet-facing administrative access, and audit devices for unauthorized admin accounts created since late 2024.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2024-55591
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2024-55591
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2025-01-21 (past due).
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Official fix for CVE-2024-55591
The authoritative fix and affected-version list are published by the vendor. Find the FortiOS and FortiProxy advisory on Fortinet PSIRT Advisories.
Common questions about CVE-2024-55591
Is CVE-2024-55591 actively exploited?
Yes. CVE-2024-55591 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2025-01-14, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 98%. CISA also reports it is known to be used in ransomware campaigns.
What is the CISA deadline and required action for CVE-2024-55591?
CISA set the federal (BOD 22-01) remediation due date at 2025-01-21, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
What fixes CVE-2024-55591?
The authoritative fix is in the vendor advisory: see Fortinet PSIRT Advisories for the patched FortiOS and FortiProxy versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2024-55591?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2024-55591's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
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Authoritative references
Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.
