{"cve":"CVE-2021-31166","nvd":{"published":"2021-05-11T19:15:09.300","modified":"2026-06-17T03:51:21.910","status":"Analyzed","description":"HTTP Protocol Stack Remote Code Execution Vulnerability","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-416"],"references":["http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html","https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166","http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html","https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166","https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166"],"products":["microsoft:windows_10_2004","microsoft:windows_10_20h2","microsoft:windows_server_2004","microsoft:windows_server_20h2"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-31166","score":0.99867,"percentile":0.99963,"date":"2026-10-31"},"kev":{"cve":"CVE-2021-31166","date_added":"2022-04-06","due_date":"2022-04-27","vendor":"Microsoft","product":"HTTP Protocol Stack","known_ransomware":false},"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}