CVE-2024-55591 — Fortios
CRITICALCVE-2024-55591 is a critical-severity (CVSS 9.8) CWE-288 vulnerability in fortinet fortios. It is in CISA's Known Exploited Vulnerabilities catalog (added 2025-01-14) and has been used in ransomware campaigns — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.
An Authentication Bypass Using an Alternate Path or Channel vulnerability [CWE-288] affecting FortiOS version 7.0.0 through 7.0.16 and FortiProxy version 7.0.0 through 7.0.19 and 7.2.0…
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2025-01-14 — including use in ransomware campaigns. Federal agencies were required to remediate by 2025-01-21.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2024-55591.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2024-55591 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).
Where this sits among everything scored
Of 395,249 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.
Description
An Authentication Bypass Using an Alternate Path or Channel vulnerability [CWE-288] affecting FortiOS version 7.0.0 through 7.0.16 and FortiProxy version 7.0.0 through 7.0.19 and 7.2.0 through 7.2.12 allows a remote attacker to gain super-admin privileges via crafted requests to Node.js websocket module.
Affected Products
fortiosfortinetfortiproxyfortinetResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every fortinet fortios deployment and check each version against the affected-products list above.
Remediation status
No patch has shipped for CVE-2024-55591 yet — track the fortinet fortios advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
How to detect CVE-2024-55591
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2024-55591 -u https://target- Template
- Fortinet - Authentication Bypass
- Severity
- critical
- Impact
- Unauthenticated attackers can bypass authentication mechanisms to access sensitive system information and gain unauthorized access to FortiOS and FortiProxy systems.
- Remediation
- Update Fortinet FortiOS and FortiProxy to versions that patch CVE-2024-55591 as specified in Fortinet's security advisory.
Template by ProjectDiscovery nuclei-templates (rootxharsh, iamnoooob, pdresearch), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2024-55591 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.