CVEs / CVE-2021-33771
CVE-2021-33771: Microsoft Windows Kernel Privilege Escalation Vulnerability
- Known exploited in the CISA KEV catalog since 3 Nov 2021
- high 7.2 CVSS 2.0 (NVD)
- EPSS 10.1% chance of exploitation in the next 30 days, higher than 95% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
Microsoft Windows kernel contains an unspecified vulnerability that allows for privilege escalation.
Description
Windows Kernel Elevation of Privilege Vulnerability
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Windows 10 Version 1507 | from 10.0.10240.0, before 10.0.10240.19003 | 10.0.10240.19003 |
| Microsoft Windows 10 Version 1607 | from 10.0.14393.0, before 10.0.14393.4530 | 10.0.14393.4530 |
| Microsoft Windows 10 Version 1809 | from 10.0.17763.0, before 10.0.17763.2061 | 10.0.17763.2061 |
| Microsoft Windows 10 Version 1809 | from 10.0.0, before 10.0.17763.2061 | 10.0.17763.2061 |
| Microsoft Windows 10 Version 1909 | from 10.0.0, before 10.0.18363.1679 | 10.0.18363.1679 |
| Microsoft Windows 10 Version 2004 | from 10.0.0, before 10.0.19041.1110 | 10.0.19041.1110 |
| Microsoft Windows 10 Version 20H2 | from 10.0.0, before 10.0.19042.1110 | 10.0.19042.1110 |
| Microsoft Windows 10 Version 21H1 | from 10.0.0, before 10.0.19043.1110 | 10.0.19043.1110 |
| Microsoft Windows 8.1 | from 6.3.0, before 6.3.9600.20069 | 6.3.9600.20069 |
| Microsoft Windows Server 2012 R2 | from 6.3.9600.0, before 6.3.9600.20069 | 6.3.9600.20069 |
| Microsoft Windows Server 2012 R2 (Server Core installation) | from 6.3.9600.0, before 6.3.9600.20069 | 6.3.9600.20069 |
| Microsoft Windows Server 2016 | from 10.0.14393.0, before 10.0.14393.4530 | 10.0.14393.4530 |
| Microsoft Windows Server 2016 (Server Core installation) | from 10.0.14393.0, before 10.0.14393.4530 | 10.0.14393.4530 |
| Microsoft Windows Server 2019 | from 10.0.17763.0, before 10.0.17763.2061 | 10.0.17763.2061 |
| Microsoft Windows Server 2019 (Server Core installation) | from 10.0.17763.0, before 10.0.17763.2061 | 10.0.17763.2061 |
| Microsoft Windows Server version 2004 | from 10.0.0, before 10.0.19041.1110 | 10.0.19041.1110 |
| Microsoft Windows Server version 20H2 | from 10.0.0, before 10.0.19042.1110 | 10.0.19042.1110 |
Exploitation
| In CISA KEV since | 3 Nov 2021 |
|---|---|
| Due date for US federal agencies | 17 Nov 2021 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply updates per vendor instructions. |
Severity
| CVSS 2.0 | 7.2 highAV:L/AC:L/Au:N/C:C/I:C/A:CScored by NVD |
|---|
References
- CVE-2021-33771 on NVD
- CVE-2021-33771 in the CISA KEV catalog
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-33771 Patch, Vendor Advisory
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33771 Patch, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33771 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.