CVE & CISA-KEV Catalog

CVE-2021-26863

HIGHEPSS 96th pctl
7.0
CVSS v3
NVD

Description

Windows Win32k Elevation of Privilege Vulnerability

CWE-269Improper Privilege Management

How to fix

Remediation Available
Windows 10 Version 1803Windows
Install:KB5000809Microsoft
Windows 10 Version 1809Windows
Install:KB5000822Microsoft
Windows 10 Version 1909Windows
Install:KB5000808Microsoft
Windows 10 Version 2004Windows
Install:KB5000802Microsoft
Windows 10 Version 20H2Windows
Install:KB5000802Microsoft
Windows Server 2019Windows
Install:KB5000822Microsoft
Windows Server 2019 (Server Core installation)Windows
Install:KB5000822Microsoft
Windows Server, version 1909 (Server Core installation)Windows
Install:KB5000808Microsoft
Windows Server, version 2004 (Server Core installation)Windows
Install:KB5000802Microsoft
Windows Server, version 20H2 (Server Core Installation)Windows
Install:KB5000802Microsoft

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal
Attack ComplexityHigh
Privileges RequiredLow
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

12.23%probability of exploitation in 30 days
96thpercentile

Very high risk: more likely to be exploited than 96% of all known CVEs.

References

Related Vulnerabilities

Other CWE-269 (Improper Privilege Management) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2017-12635Critical9.8100%-Fix
CVE-2022-24637Critical9.899%-Fix
CVE-2017-5689Critical9.892%KEVFix
CVE-2020-3243Critical9.888%--
CVE-2024-21888High8.887%--
CVE-2022-0441Critical9.885%-Fix

Common questions

How do I fix CVE-2021-26863?

Published advisories record a fix for 10 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2021-26863 being actively exploited?

Not that we know of. CVE-2021-26863 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 12.2% is the estimated probability that it will be exploited in the next 30 days. That is higher than 96% of all scored CVEs.

How severe is CVE-2021-26863?

CVE-2021-26863 has a CVSS v3 base score of 7.0, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2021-26863 affect?

Published advisories record a fix for Windows 10 Version 1803 (Windows), Windows 10 Version 1809 (Windows), Windows 10 Version 1909 (Windows), Windows 10 Version 2004 (Windows), and 6 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.