Background exploitation KEV catalog Ransomware No authentication
CVE-2024-55591

Fortinet FortiOS and FortiProxy Authentication Bypass Vulnerability

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…

CheckOps priority index
9.7/10 Patch within 24 h
Severity9.6
Probability9.4
Exploitation5/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 94.3% higher than 99.9% of CVEs
CVSS 3.1 9.6 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:
Exploited for 658 days 14 Jan 2025
CISA due date 21 Jan 2025 for US federal agencies

Exploitation probability EPSS · FIRST

05010025 Sep05 Oct15 Oct24 Oct02 Nov
EPSS probability (%)Percentile among all CVEs

Exploitation signals 5 / 5

  • KEV catalog (CISA)14 Jan 2025
  • Exploited in EUVD (ENISA)14 Jan 2025
  • Used by ransomwareyes
  • EPSS above 10 %94.3%
  • No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

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

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Description ENISA EUVD

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

FortiOSFortiProxyFortiOS and FortiProxy
Affected versions
  • 7.0.0 ≤7.0.16
  • 7.2.0 ≤7.2.12
  • 7.0.0 ≤7.0.19
Weaknesses (CWE)

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

  1. Published

  2. Exploitation reported (ENISA)

  3. Added to the KEV catalog

  4. CISA remediation due date

  5. EPSS peak: 94.3%

References

Other exploited vulnerabilities from the same vendor

  • CVE-2025-61624Fortinet Multiple Products Path Traversal Vulnerability
    3.4 · Rising fast
  • CVE-2026-104286Fortinet FortiMail Path Traversal Vulnerability
    5.9 · Actively exploited
  • CVE-2025-25249Fortinet Multiple Products Heap-based Buffer Overflow Vulnerability
    4.9 · Actively exploited
  • CVE-2025-68686Fortinet FortiOS Exposure of Sensitive Information to an Unauthorized Actor Vulnerability
    5.4 · Actively exploited
  • CVE-2026-39808Fortinet FortiSandbox OS Command Injection Vulnerability
    8.8 · Actively exploited
  • CVE-2026-25089Fortinet FortiSandbox OS Command Injection Vulnerability
    8.3 · Actively exploited

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Sources: CISA KEV · ENISA EUVD · FIRST EPSS · OSV. Public data aggregated by CheckOps, updated automatically. Source texts remain the property of their authors. All exploited vulnerabilities