# CVE-2021-40450: Microsoft Win32k Privilege Escalation Vulnerability

Source: https://junglewise.ai/threats/cve-2021-40450-microsoft-win32k-privilege-escalation-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2022-04-25. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-2021-40450 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2022-04-25

Microsoft Win32k contains an elevation of privilege vulnerability that allows a local attacker to gain system-level privileges. The flaw is caused by insufficient restrictions within the Win32k kernel-mode driver. This vulnerability has been observed being exploited in the wild.

Technologies: [Microsoft Win32K](https://junglewise.ai/threats/technologies/win32k). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2021-40450 exploited in the wild?** Yes. CVE-2021-40450 is known to be exploited in the wild, first recorded on 25 April 2022. Treat it as urgent.

**How severe is CVE-2021-40450?** Critical severity, with a CVSS score of 7.8, published 25 April 2022.

**Which products and versions are affected?** Microsoft Windows 10 1809, 1909, 2004, 20H2, 21H1; Microsoft Windows 11 21H2; Microsoft Windows Server 2004, 20H2, 2019, 2022.

**Is there a fix for CVE-2021-40450?** 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-2021-40450 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2021-40450?** Check whether you run Microsoft Win32K. 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, 1909, 2004, 20H2, 21H1
- Microsoft Windows 11 21H2
- Microsoft Windows Server 2004, 20H2, 2019, 2022

## Timeline

- 2021-10-19: disclosed: Initial analysis by NIST and Microsoft advisory release
- 2022-04-25: kev added: Added to CISA's Known Exploited Vulnerabilities Catalog

## Related threats

- [Microsoft Win32k Privilege Escalation Vulnerability](https://junglewise.ai/threats/cve-2016-0165-microsoft-win32k-privilege-escalation-vulnerability)
- [Microsoft Win32K Privilege Escalation Vulnerability](https://junglewise.ai/threats/cve-2023-29336-microsoft-win32k-privilege-escalation-vulnerability)
- [Microsoft Win32k Privilege Escalation Vulnerability](https://junglewise.ai/threats/cve-2015-2360-microsoft-win32k-privilege-escalation-vulnerability)
- [Microsoft Win32k Privilege Escalation Vulnerability](https://junglewise.ai/threats/cve-2018-8589-microsoft-win32k-privilege-escalation-vulnerability)
- [Microsoft Win32k Privilege Escalation Vulnerability](https://junglewise.ai/threats/cve-2014-4113-microsoft-win32k-privilege-escalation-vulnerability)