CVE-2021-31951

Local privilege escalation through undisclosed kernel flaw

Published Jun 8, 2021 · Updated Aug 3, 2024

Elevation of privilege in the Microsoft Windows Kernel allows local users on affected Windows 10 and Server builds to gain elevated privileges. Microsoft has not published the vulnerable kernel locus or the operation it performs incorrectly. Exploitation requires low-privilege local access and no user interaction, and successful exploitation grants control beyond the initiating account.

CVSS severity7.8
High
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Elevation of privilege in the Microsoft Windows Kernel allows local users on affected Windows 10 and Server builds to gain elevated privileges. Microsoft has not published the vulnerable kernel locus or the operation it performs incorrectly. Exploitation requires low-privilege local access and no user interaction, and successful exploitation grants control beyond the initiating account.

The record

CVE
CVE-2021-31951
Published
Jun 8, 2021
Updated
Aug 3, 2024
Vendor
Microsoft
Product
Windows Server 2019
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=10.0.0 <10.0.17763.1999

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows Server 2019version=10.0.0 <10.0.17763.1999
Microsoft · Windows 10 Version 21H1version=10.0.0 <10.0.19043.1052
Microsoft · Windows 10 Version 1909version=10.0.0 <10.0.18363.1621
Microsoft · Windows Server, version 2004version=10.0.0 <10.0.19041.1052
Microsoft · Windows 10 Version 20H2version=10.0.0 <10.0.19042.1052
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.0 <10.0.17763.1999
Microsoft · Windows Server version 20H2version=10.0.0 <10.0.19042.1052
Microsoft · Windows 10 Version 2004version=10.0.0 <10.0.19041.1052
Microsoft · Windows 10 Version 1809version=10.0.0 <10.0.17763.1999

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
6.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
7.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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

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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