9.8

CVE-2024-55591: Fortinet FortiOS and FortiProxy Authentication Bypass Vulnerability

CVSS: 9.8v3.1CriticalKEVRansomwareAnalyzed
Published 14-01-2025Last modified 05-08-2026
Open JSON

Vulnerability summary

CVE-2024-55591 is a critical (CVSS 9.8) vulnerability in Fortinet FortiOS and FortiProxy. It is known to be exploited: CISA and ENISA list it, first on 14-01-2025. It has been used in ransomware campaigns. EPSS estimates a 94.35% chance of exploitation in the next 30 days, higher than 99.8% of scored vulnerabilities.

Overall risk
90/100
0100
Critical · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (NVD)
EPSS score
94.35%
0%100%
Critical · -3.91 pp in 30 days
KEVListedCISA · ENISA
RansomwareKnown useFlagged by CISA, ENISA
Public exploits0No public exploits recorded

Timeline

  1. 14-01-2025
    PublishedVulnerability first disclosed.
  2. 14-01-2025
    Added to CISA KEVFortinet FortiOS and FortiProxy Authentication Bypass Vulnerability
  3. 21-01-2025
    CISA remediation dueApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
  4. 13-02-2025
    Added to ENISA KEVAdded to the ENISA known exploited vulnerabilities catalog.
  5. 05-08-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

94.35%

Chance of exploitation in the next 30 days

Percentile

100%

Versus all other CVEs

30-day change

-3.91 pp

From 98.26% on 21-09-2026

21-09-202621-10-2026
EPSS score
94.35%

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
14-01-2025
Federal due date
21-01-2025
Ransomware
ENISA CNWListed
Added
13-02-2025
Ransomware

CISA required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. fortiguard.fortinet.com/psirt/FG-IR-24-535 nvd.nist.gov/vuln/detail/CVE-2024-55591

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Fortinet2 products
  • fortios≥ 7.0.0, ≤ 7.0.16 | ≥ 7.0.0, < 7.0.17
  • fortiproxy≥ 7.2.0, ≤ 7.2.12 | ≥ 7.0.0, ≤ 7.0.19 | ≥ 7.0.0, < 7.0.20 | ≥ 7.2.0, < 7.2.13

1 vendor · 2 products

References

2 links