# CVE-2021-31166

HTTP Protocol Stack Remote Code Execution Vulnerability

- Page: https://www.vulneraibility.com/cve/CVE-2021-31166
- CVSS: 9.8
- Known exploited: yes, in CISA KEV since 2022-04-06; CISA due date 2022-04-27
- EPSS: 99.87% (percentile 100.0)
- Unvetted proof-of-concept code on GitHub: 1 Metasploit module · 12 GitHub proofs of concept (first 2021-05-16)
- CISA SSVC: exploitation active, automatable yes, technical impact total (assessed 2025-02-07)
- Weakness: CWE-416
- Published: 2021-05-11

## Affected versions

- Microsoft Windows 10 Version 2004: affected >= 10.0.0 and < 10.0.19041.982
- Microsoft Windows 10 Version 20H2: affected >= 10.0.0 and < 10.0.19042.982
- Microsoft Windows Server version 2004: affected >= 10.0.0 and < 10.0.19041.982
- Microsoft Windows Server version 20H2: affected >= 10.0.0 and < 10.0.19042.982

A version outside these ranges is not a statement that it is unaffected.

## References

- [other] https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166
- [other] http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.