Is CVE-2024-21338 being actively exploited?

Yes. CVE-2024-21338 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added on March 4, 2024.

What is the CVSS score for CVE-2024-21338?

CVE-2024-21338 has a CVSS 3.1 base score of 7.8 (HIGH).

CVE-2024-21338

HIGH · CVSS 7.8CISA KEV: actively exploitedEPSS 59.8%EU EUVD: exploited

Windows Kernel Elevation of Privilege Vulnerability

Key facts

CVSS score: 7.8 (v3.1)
Severity: HIGH
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-822
EPSS score: 59.8% (99th percentile)
In CISA KEV: Yes, added March 4, 2024
In EU EUVD: Yes (EUVD-2024-19050)
Published: February 13, 2024
NVD last modified: August 10, 2026
Status: Analyzed

CISA Known Exploited Vulnerability

Microsoft Windows Kernel Exposed IOCTL with Insufficient Access Control Vulnerability

Added to the KEV catalog on March 4, 2024; federal remediation due March 25, 2024. Known to be used in ransomware campaigns.

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2024-19050 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on August 10, 2026.

View on the EU Vulnerability Database

Affected products

microsoft / windows 10 1809
microsoft / windows 10 21h2
microsoft / windows 10 22h2
microsoft / windows 11 21h2
microsoft / windows 11 22h2
microsoft / windows 11 23h2
microsoft / windows server 2019
microsoft / windows server 2022
microsoft / windows server 2022 23h2

Certified products that may be affected

1 FIPS 140 or Common Criteria certified product, from automated matching by sec-certs.org.

Microsoft Windows 10 and Server version 1903 (May 2019 Update) - Microsoft Corporation - Common Criteria 2019-22-INF-2839 - archived

References

https://decoded.avast.io/janvojtesek/lazarus-and-the-fudmodule-rootkit-beyond-byovd-with-an-admin-to-kernel-zero-day/(Exploit, Technical Description, Third Party Advisory)
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21338(Patch, Vendor Advisory)
https://packetstorm.news/files/id/190586/(Exploit, VDB Entry)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-21338(US Government Resource)
https://www.exploit-db.com/exploits/52275(Exploit, VDB Entry)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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