CVE-2021-43239

Local privilege escalation

Published Dec 15, 2021 · Updated Aug 4, 2024

Elevation of privilege in Microsoft Windows Recovery Environment Agent allows local users with low privileges to gain elevated rights. Microsoft has not published the flawed operation or input path within the Windows Recovery Environment Agent. Exploitation requires local low-privileged access and can alter protected data or interrupt service, while Microsoft reports no confidentiality impact.

CVSS severity7.1
High
EPSS probability0.54%
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 Microsoft Windows Recovery Environment Agent allows local users with low privileges to gain elevated rights. Microsoft has not published the flawed operation or input path within the Windows Recovery Environment Agent. Exploitation requires local low-privileged access and can alter protected data or interrupt service, while Microsoft reports no confidentiality impact.

The record

CVE
CVE-2021-43239
Published
Dec 15, 2021
Updated
Aug 4, 2024
Vendor
Microsoft
Product
Windows 10 Version 21H1
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 15, 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

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 <10.0.19043.1415

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows 10 Version 21H1version=10.0.0 <10.0.19043.1415
Microsoft · Windows 11 version 21H2version=10.0.0 <10.0.22000.376
Microsoft · Windows Server, version 2004version=10.0.0 <10.0.19041.1415
Microsoft · Windows 10 Version 21H2version=10.0.0 <10.0.19044.1415
Microsoft · Windows 10 Version 20H2version=10.0.0 <10.0.19042.1415
Microsoft · Windows Server version 20H2version=10.0.0 <10.0.19042.1415
Microsoft · Windows Server 2022version=10.0.0 <10.0.20348.405
Microsoft · Windows 10 Version 2004version=10.0.0 <10.0.19041.1415

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.1Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P

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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