How severe is CVE-2024-21338?

CVE-2024-21338 has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2024-21338?

Affected package information for CVE-2024-21338 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2024-21338?

No fixed version has been published for CVE-2024-21338 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2024-21338 actively exploited in the wild?

Yes. There are 16 known exploit references for CVE-2024-21338, including 2 documented proof-of-concept exploits on Exploit-DB and 9 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

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

CVE-2024-21338 has an EPSS (Exploit Prediction Scoring System) score of 79.4%, placing it in the 99th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2024-21338 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2024-21338 (Microsoft Windows Kernel Exposed IOCTL with Insufficient Access Control Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2024-03-04. CISA required all US federal civilian agencies to remediate this vulnerability by 2024-03-25. The required action was: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. This CVE has been used in known ransomware campaigns. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2024-21338?

CVE-2024-21338 is classified as CWE-822 (CWE-822). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2024-21338?

CVE-2024-21338 affects microsoft windows 10 21h2; microsoft windows 10 22h2; microsoft windows 10 1809; microsoft windows 11 21h2, and 5 more product(s). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2024-21338 published, and has it been updated?

CVE-2024-21338 was published on February 13, 2024 and was last updated on October 28, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2024-03-04 — agencies required to remediate by 2024-03-25 · Ransomware

CVE-2024-21338

HIGH

Windows Kernel Elevation of Privilege Vulnerability

Published

Feb 13, 2024

Updated

Oct 28, 2025

Affected

0 pkgs

Patched

None yet

Exploits

16 known

EPSS Exploitation Probability

via FIRST.org ↗

79.4%probability of exploitation in next 30 days

Very High Risk99th percentile-0.21%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

Windows Kernel Elevation of Privilege Vulnerability

Affected Products

9 products · 9 configurations

windows 10 21h2microsoft

< 10.0.19044.4046

range

windows 10 22h2microsoft

< 10.0.19045.4046

range

windows 10 1809microsoft

< 10.0.17763.5458

range

windows 11 21h2microsoft

< 10.0.22000.2777

range

windows 11 22h2microsoft

< 10.0.22621.3155

range

windows 11 23h2microsoft

< 10.0.22631.3155

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-51946localwindows

Microsoft Windows 10.0.17763.5458 - Kernel Privilege Escalation

by E1 Coders · Apr 2, 2024

Exploit-DB Source

EDB-52275localwindows

Microsoft Windows 11 - Kernel Privilege Escalation

by Milad karimi · Apr 22, 2025

Exploit-DB Source

Frequently Asked Questions

Windows Kernel Elevation of Privilege Vulnerability

O3 Security · Impact-Aware SCA

Is CVE-2024-21338 in your stack?

O3 detects CVE-2024-21338 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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