CVE-2021-43247: Microsoft Windows tcpip.sys Heap-based Buffer Overflow Local Privilege Escalation Vulnerability

Published Dec 14, 2021
·
Updated

This vulnerability allows local attackers to escalate privileges on affected installations of Microsoft Windows. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the tcpip.sys driver. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length heap-based buffer. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM.

Other sources

Windows TCP/IP Driver Elevation of Privilege Vulnerability

Affected Software

51 affected componentsFixes available
Microsoft Windows Server=20H2
Microsoft Windows Server=2004
Microsoft Windows Server 2019
Microsoft Windows Server 2019
Microsoft Windows 11=21H2
Microsoft Windows 11=21H2
Microsoft Windows Server 2022
Microsoft Windows Server 2022
Microsoft Windows 10=20H2
Microsoft Windows 10=20H2
Microsoft Windows 10=20H2
Microsoft Windows 10=1809
Microsoft Windows 10=1809
Microsoft Windows 10=1809
Microsoft Windows 10=21H1
Microsoft Windows 10=21H1
Microsoft Windows 10=21H1
Microsoft Windows 10=21H2
Microsoft Windows 10=21H2
Microsoft Windows 10=21H2
Microsoft Windows 10=1909
Microsoft Windows 10=1909
Microsoft Windows 10=1909
Microsoft Windows 10=2004
Microsoft Windows 10=2004
Microsoft Windows 10=2004
Microsoft Windows 10=20h2
Microsoft Windows 10=20h2
Microsoft Windows 10=20h2
Microsoft Windows 10=21h1
Microsoft Windows 10=21h1
Microsoft Windows 10=21h1
Microsoft Windows 10=21h2
Microsoft Windows 10=21h2
Microsoft Windows 10=21h2
Microsoft Windows 10=1809
Microsoft Windows 10=1809
Microsoft Windows 10=1809
Microsoft Windows 10=1909
Microsoft Windows 10=1909
Microsoft Windows 10=1909
Microsoft Windows 10=2004
Microsoft Windows 10=2004
Microsoft Windows 10=2004
Microsoft Windows 11
Microsoft Windows 11
Microsoft Windows Server=20h2
Microsoft Windows Server=2022
Microsoft Windows Server 2016=2004
Microsoft Windows Server 2019
Microsoft Windows

Event History

Dec 14, 2021
CVE Published
via Microsoft·08:00 AM
Data Sourced
via Microsoft·08:00 AM
DescriptionSeverityWeakness
Dec 15, 2021
CVE Published
via MITRE·02:15 PM
Data Sourced
via MITRE·02:15 PM
DescriptionSeverity
Apr 1, 2025
Advisory Published
via ZDI·05:16 PM

Frequently Asked Questions

1

What is the severity of CVE-2021-43247?

CVE-2021-43247 has a severity rating of Important according to Microsoft's vulnerability scoring.

2

How do I fix CVE-2021-43247?

To patch CVE-2021-43247, users should apply updates provided by Microsoft, specifically KB5008212.

3

Which versions of Windows are affected by CVE-2021-43247?

Windows 10 versions 1809, 1909, 2004, 20H2, 21H1, and 21H2, as well as Windows Server versions, are affected by CVE-2021-43247.

4

Can CVE-2021-43247 be exploited remotely?

No, CVE-2021-43247 requires local access to the machine in order to exploit the vulnerability.

5

What kind of attacks can be executed using CVE-2021-43247?

CVE-2021-43247 allows local privilege escalation, enabling an attacker to execute code with elevated permissions.

Contact

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