Security CISA KEV CVE-2021-31166 CVE-2021-31166 CISA KEV
Microsoft HTTP Protocol Stack Remote Code Execution Vulnerability
Severity unknown CVSS unknown Check the vendor advisory for fixed versions
CISA lists this Microsoft vulnerability as known exploited. Its MSRC release detail is outside this installation's collected history.
CISA catalog record
Microsoft HTTP Protocol Stack contains a vulnerability in http.sys that allows for remote code execution.
Product HTTP Protocol Stack
Added to KEV 6 Apr 2022
Federal remediation due 27 Apr 2022
Known ransomware use Not reported Page history
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23 Oct 2026 · 09:33:49 UTC
Source coverage: cisa-kev Incomplete → Current 23 Oct 2026 · 08:31:50 UTC
Source coverage: cisa-kev Current → Incomplete Explore global source statements, affected packages and advisory history for CVE-2021-31166 . The catalog has a separate collection scope from Microsoft release records.
More advisories, affected versions and source history Overview Affected History Connections
Related advisories and sources Publishers link these advisories through the identifiers shown below. A shared identifier or date alone does not tell you whether your software is affected or whether the advisories describe the same cause.
CVE-2021-31166 · CVE overview and exploitation status
cve-program · CVE-2021-31166
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