Background exploitation KEV catalog Ransomware No authentication

CVE-2024-21762

Fortinet FortiOS Out-of-Bound Write Vulnerability

CheckOps priority index

9.4/10 Patch within 24 h

Severity9.6

Probability8.5

Exploitation5/5

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

EPSS · today 84.6% higher than 99.7% of CVEs

CVSS 3.1 9.6 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:

Exploited for 998 days 09 Feb 2024

CISA due date 16 Feb 2024 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 5 / 5

KEV catalog (CISA)09 Feb 2024
Exploited in EUVD (ENISA)09 Feb 2024
Used by ransomwareyes
EPSS above 10 %84.6%
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

A out-of-bounds write vulnerability in Fortinet FortiOS 7.4.0 through 7.4.2, FortiOS 7.2.0 through 7.2.6, FortiOS 7.0.0 through 7.0.13, FortiOS 6.4.0 through 6.4.14, FortiOS 6.2.0 through 6.2.15, FortiOS 6.0 all versions, FortiProxy 7.4.0 through 7.4.2, FortiProxy 7.2.0 through 7.2.8, FortiProxy 7.0.0 through 7.0.14, FortiProxy 2.0.0 through 2.0.13, FortiProxy 01.02 all versions, FortiProxy 1.2 all versions, FortiProxy 01.01 all versions, FortiProxy 1.1 all versions, FortiProxy 01.00 all versions allows attacker to execute unauthorized code or commands via specifically crafted requests

Affected products

FortiOSFortiProxy

Affected versions

7.2.0 ≤7.2.6
6.2.0 ≤6.2.15
7.0.0 ≤7.0.14
01.02.00
6.0.0 ≤6.0.18
1.2.1 ≤1.2.13
7.0.0 ≤7.0.13
6.4.0 ≤6.4.14
7.2.0 ≤7.2.8
1.1.4 ≤1.1.6
7.4.0 ≤7.4.2
01.01.00 ≤01.01.03

Weaknesses (CWE)

CWE-787

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

09 Feb 2024
Published
09 Feb 2024
Exploitation reported (ENISA)
09 Feb 2024
Added to the KEV catalog
16 Feb 2024
CISA remediation due date
25 Oct 2026
EPSS peak: 84.6%

References

Other exploited vulnerabilities from the same vendor

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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