CVE-2021-43247: Microsoft Windows tcpip.sys Heap-based Buffer Overflow Local Privilege Escalation Vulnerability
First published: Tue 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.
Credit: secure@microsoft.com secure@microsoft.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Microsoft Windows 10 | =20H2 | |
| 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 | ||
| Microsoft Windows 10 | =20H2 | |
| Microsoft Windows 10 | =2004 | |
| Microsoft Windows Server | =20H2 | |
| Microsoft Windows Server 2022 | ||
| Microsoft Windows 10 | =21H2 | |
| Microsoft Windows 10 | =1909 | |
| Microsoft Windows 10 | =21H1 | |
| Microsoft Windows 10 | =1809 | |
| Microsoft Windows 10 | =21H2 | |
| Microsoft Windows Server 2019 | ||
| Microsoft Windows 10 | =21H1 | |
| Microsoft Windows 10 | =20H2 | |
| Microsoft Windows 10 | =1909 | |
| Microsoft Windows 10 | =1909 | |
| Microsoft Windows 10 | =2004 | |
| Microsoft Windows 11 | =21H2 | |
| Microsoft Windows 10 | =21H1 | |
| Microsoft Windows 10 | =21H2 | |
| Microsoft Windows 11 | =21H2 | |
| Microsoft Windows Server 2019 | ||
| Microsoft Windows 10 | =1809 | |
| Microsoft Windows Server 2022 | ||
| Microsoft Windows 10 | =2004 | |
| Microsoft Windows 10 | =1809 | |
| Microsoft Windows Server | =2004 | |
| =20h2 | ||
| =20h2 | ||
| =20h2 | ||
| =21h1 | ||
| =21h1 | ||
| =21h1 | ||
| =21h2 | ||
| =21h2 | ||
| =21h2 | ||
| =1809 | ||
| =1809 | ||
| =1809 | ||
| =1909 | ||
| =1909 | ||
| =1909 | ||
| =2004 | ||
| =2004 | ||
| =2004 | ||
| =20h2 | ||
| =2022 | ||
| =2004 | ||
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2021-43247?
CVE-2021-43247 has a severity rating of Important according to Microsoft's vulnerability scoring.
How do I fix CVE-2021-43247?
To patch CVE-2021-43247, users should apply updates provided by Microsoft, specifically KB5008212.
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.
Can CVE-2021-43247 be exploited remotely?
No, CVE-2021-43247 requires local access to the machine in order to exploit the vulnerability.
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.
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