{"id":"CVE-2021-31166","aliases":[],"url":"https://o3.security/vulnerability/CVE-2021-31166","summary":"HTTP Protocol Stack Remote Code Execution Vulnerability","details":"HTTP Protocol Stack Remote Code Execution Vulnerability","published":"2021-05-11T19:15:09.300","modified":"2026-06-17T03:51:21.910","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.99772,"percentile":0.99954,"asOf":"2026-09-08"},"cisaKev":null,"exploitsKnown":26,"affectedPackages":[],"fix":null,"references":[{"type":"ADVISORY","url":"http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html"},{"type":"FIX","url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166"},{"type":"ADVISORY","url":"http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html"},{"type":"FIX","url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166"},{"type":"WEB","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-06-17T03:51:21.910"}}