#VU53113 Use-after-free in Windows and Windows Server - CVE-2021-31166

Vulnerability identifier: #VU53113

Vulnerability risk: High

CVSSv4.0: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber]

CVE-ID: CVE-2021-31166

CWE-ID: CWE-416

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Windows
Operating systems & Components / Operating system
Windows Server
Operating systems & Components / Operating system

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error in HTTP Protocol Stack. A remote attacker can send a specially crafted HTTP request to the affected system and execute arbitrary code.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Windows: 10 20H2 10.0.19042.572, 10 2004 10.0.19041.264

Windows Server: 2019 20H2 - 2019 2004

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External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.