CVE-2021-41339

Local privilege escalation

Published Oct 13, 2021 · Updated Aug 4, 2024

Improper privilege management in Microsoft Windows DWM Core Library allows local users with low privileges to gain elevated privileges. Public research identifies CCompositionGlyphRun::ProcessSetBrush as the affected locus, where a caller-controlled brush resource is accepted across multiple object subtypes before notifier registration, but it does not disclose the precise unsafe operation. Exploitation requires low local privileges and high-complexity conditions; Microsoft's vector bounds the reported consequence to confidentiality loss, without integrity or availability impact.

CVSS severity4.7
Medium
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper privilege management in Microsoft Windows DWM Core Library allows local users with low privileges to gain elevated privileges. Public research identifies CCompositionGlyphRun::ProcessSetBrush as the affected locus, where a caller-controlled brush resource is accepted across multiple object subtypes before notifier registration, but it does not disclose the precise unsafe operation. Exploitation requires low local privileges and high-complexity conditions; Microsoft's vector bounds the reported consequence to confidentiality loss, without integrity or availability impact.

The record

CVE
CVE-2021-41339
Published
Oct 13, 2021
Updated
Aug 4, 2024
Vendor
Microsoft
Product
Windows 10 Version 21H1
Classifications
CWE-269, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.0 <10.0.19043.1288

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows 10 Version 21H1version=10.0.0 <10.0.19043.1288
Microsoft · Windows 10 Version 1909version=10.0.0 <10.0.18363.1854
Microsoft · Windows 11 version 21H2version=10.0.0 <10.0.22000.258
Microsoft · Windows Server, version 2004version=10.0.0 <10.0.19041.1288
Microsoft · Windows 10 Version 20H2version=10.0.0 <10.0.19042.1288
Microsoft · Windows Server version 20H2version=10.0.0 <10.0.19042.1288
Microsoft · Windows Server 2022version=10.0.0 <10.0.20348.288
Microsoft · Windows 10 Version 2004version=10.0.0 <10.0.19041.1288

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.6NVDAV:L/AC:L/Au:N/C:P/I:P/A:P
4.7MicrosoftCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-269Improper Privilege Management
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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