# CVE-2021-31979: Microsoft Windows Kernel Privilege Escalation Vulnerability

Source: https://junglewise.ai/threats/cve-2021-31979-microsoft-windows-kernel-privilege-escalation-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-11-03. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-2021-31979 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2021-11-03

A privilege escalation vulnerability exists in the Microsoft Windows Kernel due to improper restriction of operations within the bounds of a memory buffer (CWE-119). An attacker who successfully exploits this vulnerability could gain elevated system privileges.

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

## Quick answers

**Is CVE-2021-31979 exploited in the wild?** Yes. CVE-2021-31979 is known to be exploited in the wild, first recorded on 3 November 2021. Treat it as urgent.

**How severe is CVE-2021-31979?** Critical severity, with a CVSS score of 7.8, published 3 November 2021.

**Which products and versions are affected?** Microsoft Windows 10 1507, 1607, 1809, 1909, 2004, 20H2, 21H1; Microsoft Windows 7 SP1; Microsoft Windows 8.1; Microsoft Windows RT 8.1; and 6 more.

**Is there a fix for CVE-2021-31979?** 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-2021-31979 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2021-31979?** 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 1507, 1607, 1809, 1909, 2004, 20H2, 21H1
- Microsoft Windows 7 SP1
- Microsoft Windows 8.1
- Microsoft Windows RT 8.1
- Microsoft Windows Server 2008 SP2, R2 SP1
- Microsoft Windows Server 2012 Base, R2
- Microsoft Windows Server 2016
- Microsoft Windows Server 2019
- Microsoft Windows Server 2004
- Microsoft Windows Server 20H2

## Timeline

- 2021-11-03: advisory: Microsoft published the security advisory.
- 2021-11-03: kev added: Added to CISA Known Exploited Vulnerabilities (KEV) catalog.
- 2021-11-03: exploited: Vulnerability reported as being exploited in the wild.

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