# CVE-2024-21338: Microsoft Windows Kernel Exposed IOCTL with Insufficient Access Control Vulnerability

Source: https://junglewise.ai/threats/cve-2024-21338-microsoft-windows-kernel-exposed-ioctl-with-insufficient-access  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2024-03-04. Updated: 2026-05-09  
License: CC BY 4.0 with a link back

CVE-2024-21338 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2024-03-04

The Microsoft Windows Kernel contains an exposed IOCTL dispatcher in the appid.sys driver with insufficient access control. A local attacker can exploit this vulnerability to achieve elevation of privilege, potentially gaining kernel-level execution.

Technologies: [Microsoft Windows](https://junglewise.ai/threats/technologies/windows). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2024-21338 exploited in the wild?** Yes. CVE-2024-21338 is known to be exploited in the wild, first recorded on 4 March 2024. Treat it as urgent.

**How severe is CVE-2024-21338?** Critical severity, with a CVSS score of 7.8, published 4 March 2024.

**Which products and versions are affected?** Microsoft Windows 10 1809 up to (excluding) 10.0.17763.5458; Microsoft Windows 10 21H2 up to (excluding) 10.0.19044.4046; Microsoft Windows 10 22H2 up to (excluding) 10.0.19045.4046; Microsoft Windows Kernel.

**Is there a fix for CVE-2024-21338?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2024-21338 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2024-21338?** Check whether you run Microsoft Windows. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Microsoft Windows 10 1809 up to (excluding) 10.0.17763.5458
- Microsoft Windows 10 21H2 up to (excluding) 10.0.19044.4046
- Microsoft Windows 10 22H2 up to (excluding) 10.0.19045.4046
- Microsoft Windows Kernel

## Timeline

- 2024-02-20: disclosed: Initial analysis by NIST
- 2024-03-04: kev added: Added to CISA Known Exploited Vulnerabilities Catalog
- 2024-03-04: exploited: Reported as exploited in the wild by Lazarus Group

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