CVE-2021-31166
Microsoft Windows 10 Version 2004, Microsoft Windows Server version 2004, Microsoft Windows 10 Version 20H2
Published 11 May 2021 · updated 17 Jun 2026 · Analyzed
9.8 Critical · CVSS 3.1, microsoft.com
Exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on 6 Apr 2022, with a remediation deadline of 27 Apr 2022 for US federal agencies.
Required action: Apply updates per vendor instructions.
Description
HTTP Protocol Stack Remote Code Execution Vulnerability
References
- packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html · Third Party Advisory, VDB Entry
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166 · Patch, Vendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166 · US Government Resource