---
id: CVE-2021-33771
title: Windows Kernel Elevation of Privilege Vulnerability
summary: Windows Kernel Elevation of Privilege Vulnerability
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
vendor: microsoft
product: windows_10_1507
affected:
  - windows_10_1507 < 10.0.10240.19003
  - windows_10_1607 < 10.0.14393.4530
  - windows_10_1809 < 10.0.17763.2061
  - windows_10_1909 < 10.0.18363.1679
  - windows_10_2004 < 10.0.19041.1110
  - windows_10_20h2 < 10.0.19042.1110
  - windows_10_21h1 < 10.0.19043.1110
  - windows_8.1
  - windows_rt_8.1
  - windows_server_2004 < 10.0.19041.1110
  - windows_server_2008
  - windows_server_2012
  - windows_server_2016 < 10.0.14393.4530
  - windows_server_2019 < 10.0.17763.2061
  - windows_server_20h2 < 10.0.19042.1110
patched:
  - windows_10_1507 10.0.10240.19003
  - windows_10_1607 10.0.14393.4530
  - windows_10_1809 10.0.17763.2061
  - windows_10_1909 10.0.18363.1679
  - windows_10_2004 10.0.19041.1110
  - windows_10_20h2 10.0.19042.1110
  - windows_10_21h1 10.0.19043.1110
  - windows_server_2004 10.0.19041.1110
  - windows_server_2016 10.0.14393.4530
  - windows_server_2019 10.0.17763.2061
  - windows_server_20h2 10.0.19042.1110
published: '2021-07-14'
updated: '2026-08-10'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-33771'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-33771'
    label: secure@microsoft.com
  - url: >-
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33771
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33771
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - kev
  - in-the-wild
epss: 0.10172
epssPercentile: 0.95502
kev: true
kevDateAdded: '2021-11-03'
kevDueDate: '2021-11-17'
kevRansomware: false
exploited: true
zeroDay: true
ingestedAt: '2026-08-10T16:41:15.538Z'
---

## Overview

Windows Kernel Elevation of Privilege Vulnerability

## Affected

- `windows_10_1507 < 10.0.10240.19003`
- `windows_10_1607 < 10.0.14393.4530`
- `windows_10_1809 < 10.0.17763.2061`
- `windows_10_1909 < 10.0.18363.1679`
- `windows_10_2004 < 10.0.19041.1110`
- `windows_10_20h2 < 10.0.19042.1110`
- `windows_10_21h1 < 10.0.19043.1110`
- `windows_8.1`
- `windows_rt_8.1`
- `windows_server_2004 < 10.0.19041.1110`
- `windows_server_2008`
- `windows_server_2012`
- `windows_server_2016 < 10.0.14393.4530`
- `windows_server_2019 < 10.0.17763.2061`
- `windows_server_20h2 < 10.0.19042.1110`

## Remediation

Upgrade past the affected range:

- `windows_10_1507 10.0.10240.19003`
- `windows_10_1607 10.0.14393.4530`
- `windows_10_1809 10.0.17763.2061`
- `windows_10_1909 10.0.18363.1679`
- `windows_10_2004 10.0.19041.1110`
- `windows_10_20h2 10.0.19042.1110`
- `windows_10_21h1 10.0.19043.1110`
- `windows_server_2004 10.0.19041.1110`
- `windows_server_2016 10.0.14393.4530`
- `windows_server_2019 10.0.17763.2061`
- `windows_server_20h2 10.0.19042.1110`