CVE-2021-31166 - Vulnerability Details - OpenCVE

HTTP Protocol Stack Remote Code Execution Vulnerability

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

Access Vector Network

Access Complexity Low

Authentication None

Confidentiality Impact Partial

Integrity Impact Partial

Availability Impact Partial

This CVE is in the KEV database since April 6, 2022.

Exploitation active

Automatable yes

Technical Impact total

Vendors	Products
Microsoft	Windows 10 1809 Windows 10 2004 Windows 10 20h2 Windows 10 20h2 Windows Server 2004 Windows Server 20h2 Windows Server 20h2

Configuration 1 [-]

OR	cpe:2.3:o:microsoft:windows_10_2004::::::::
	cpe:2.3:o:microsoft:windows_10_20h2::::::::
	cpe:2.3:o:microsoft:windows_server_2004::::::::
	cpe:2.3:o:microsoft:windows_server_20h2::::::::

No data.

References

Link	Providers
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

History

Wed, 22 Oct 2025 00:15:00 +0000

Type	Values Removed	Values Added
References		https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166

Tue, 21 Oct 2025 20:30:00 +0000

Type	Values Removed	Values Added
References	https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166

Tue, 21 Oct 2025 19:30:00 +0000

Type	Values Removed	Values Added
References		https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166

Fri, 07 Feb 2025 15:15:00 +0000

Type	Values Removed	Values Added
Metrics		kev `{'dateAdded': '2022-04-06'}` ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'active', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

MITRE

Status: PUBLISHED

Assigner: microsoft

Published: 2021-05-11T19:11:19.000Z

Updated: 2025-10-21T23:25:45.988Z

Reserved: 2021-04-14T00:00:00.000Z

Link: CVE-2021-31166

Vulnrichment

Updated: 2024-08-03T22:55:52.129Z

NVD

Status : Modified

Published: 2021-05-11T19:15:09.300

Modified: 2025-10-22T00:17:35.357

Link: CVE-2021-31166

Redhat

No data.

{"containers": {"cna": {"title": "HTTP Protocol Stack Remote Code Execution Vulnerability", "datePublic": "2021-05-11T07:00:00.000Z", "affected": [{"vendor": "Microsoft", "product": "Windows 10 Version 2004", "cpes": ["cpe:2.3:o:microsoft:windows_10_1809:10.0.19041.982:*:*:*:*:*:x64:*"], "platforms": ["32-bit Systems", "ARM64-based Systems", "x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19041.982", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server version 2004", "cpes": ["cpe:2.3:o:microsoft:windows_server_2004:10.0.19041.982:*:*:*:*:*:*:*"], "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19041.982", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 10 Version 20H2", "cpes": ["cpe:2.3:o:microsoft:windows_10_20H2:10.0.19042.982:*:*:*:*:*:x86:*", "cpe:2.3:o:microsoft:windows_10_20H2:10.0.19042.982:*:*:*:*:*:arm64:*"], "platforms": ["32-bit Systems", "ARM64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19042.982", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server version 20H2", "cpes": ["cpe:2.3:o:microsoft:windows_server_20H2:10.0.19042.982:*:*:*:*:*:*:*"], "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19042.982", "versionType": "custom", "status": "affected"}]}], "descriptions": [{"value": "HTTP Protocol Stack Remote Code Execution Vulnerability", "lang": "en-US"}], "problemTypes": [{"descriptions": [{"description": "Remote Code Execution", "lang": "en-US", "type": "Impact"}]}], "providerMetadata": {"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "shortName": "microsoft", "dateUpdated": "2023-12-28T23:56:49.266Z"}, "references": [{"tags": ["x_refsource_MISC"], "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166"}, {"tags": ["x_refsource_MISC"], "url": "http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en-US", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "baseSeverity": "CRITICAL", "baseScore": 9.8, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C"}}]}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-03T22:55:52.129Z"}, "title": "CVE Program Container", "references": [{"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html"}]}, {"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2021-31166", "role": "CISA Coordinator", "options": [{"Exploitation": "active"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2025-02-07T14:36:57.411562Z"}}}, {"other": {"type": "kev", "content": {"dateAdded": "2022-04-06", "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166"}}}], "references": [{"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166", "tags": ["government-resource"]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free"}]}], "timeline": [{"time": "2022-04-06T00:00:00+00:00", "lang": "en", "value": "CVE-2021-31166 added to CISA KEV"}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-10-21T23:25:45.988Z"}}]}, "cveMetadata": {"assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "assignerShortName": "microsoft", "cveId": "CVE-2021-31166", "datePublished": "2021-05-11T19:11:19.000Z", "dateReserved": "2021-04-14T00:00:00.000Z", "dateUpdated": "2025-10-21T23:25:45.988Z", "state": "PUBLISHED"}, "dataType": "CVE_RECORD", "dataVersion": "5.1"}

{"containers": {"cna": {"title": "HTTP Protocol Stack Remote Code Execution Vulnerability", "datePublic": "2021-05-11T07:00:00.000Z", "affected": [{"vendor": "Microsoft", "product": "Windows 10 Version 2004", "cpes": ["cpe:2.3:o:microsoft:windows_10_1809:10.0.19041.982:*:*:*:*:*:x64:*"], "platforms": ["32-bit Systems", "ARM64-based Systems", "x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19041.982", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server version 2004", "cpes": ["cpe:2.3:o:microsoft:windows_server_2004:10.0.19041.982:*:*:*:*:*:*:*"], "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19041.982", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 10 Version 20H2", "cpes": ["cpe:2.3:o:microsoft:windows_10_20H2:10.0.19042.982:*:*:*:*:*:x86:*", "cpe:2.3:o:microsoft:windows_10_20H2:10.0.19042.982:*:*:*:*:*:arm64:*"], "platforms": ["32-bit Systems", "ARM64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19042.982", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server version 20H2", "cpes": ["cpe:2.3:o:microsoft:windows_server_20H2:10.0.19042.982:*:*:*:*:*:*:*"], "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19042.982", "versionType": "custom", "status": "affected"}]}], "descriptions": [{"value": "HTTP Protocol Stack Remote Code Execution Vulnerability", "lang": "en-US"}], "problemTypes": [{"descriptions": [{"description": "Remote Code Execution", "lang": "en-US", "type": "Impact"}]}], "providerMetadata": {"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "shortName": "microsoft", "dateUpdated": "2023-12-28T23:56:49.266Z"}, "references": [{"tags": ["x_refsource_MISC"], "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166"}, {"tags": ["x_refsource_MISC"], "url": "http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en-US", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "baseSeverity": "CRITICAL", "baseScore": 9.8, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C"}}]}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-03T22:55:52.129Z"}, "title": "CVE Program Container", "references": [{"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html"}]}, {"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2021-31166", "role": "CISA Coordinator", "options": [{"Exploitation": "active"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2025-02-07T14:36:57.411562Z"}}}, {"other": {"type": "kev", "content": {"dateAdded": "2022-04-06", "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166"}}}], "references": [{"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166", "tags": ["government-resource"]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free"}]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-02-07T14:37:11.441Z"}, "timeline": [{"time": "2022-04-06T00:00:00+00:00", "lang": "en", "value": "CVE-2021-31166 added to CISA KEV"}], "title": "CISA ADP Vulnrichment"}]}, "cveMetadata": {"assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "assignerShortName": "microsoft", "cveId": "CVE-2021-31166", "datePublished": "2021-05-11T19:11:19.000Z", "dateReserved": "2021-04-14T00:00:00.000Z", "dateUpdated": "2025-10-21T19:46:44.125Z", "state": "PUBLISHED"}, "dataType": "CVE_RECORD", "dataVersion": "5.1"}

{"cisaActionDue": "2022-04-27", "cisaExploitAdd": "2022-04-06", "cisaRequiredAction": "Apply updates per vendor instructions.", "cisaVulnerabilityName": "Microsoft HTTP Protocol Stack Remote Code Execution Vulnerability", "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:microsoft:windows_10_2004:*:*:*:*:*:*:*:*", "matchCriteriaId": "F170C517-0312-457D-9108-ECA6638C8223", "versionEndExcluding": "10.0.19041.982", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_10_20h2:*:*:*:*:*:*:*:*", "matchCriteriaId": "957F366C-FD59-479A-A6C5-F93E35436549", "versionEndExcluding": "10.0.19042.982", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2004:*:*:*:*:*:*:*:*", "matchCriteriaId": "BD0A39ED-F4B4-4C2D-BDB4-088426F2377B", "versionEndExcluding": "10.0.19041.982", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_server_20h2:*:*:*:*:*:*:*:*", "matchCriteriaId": "F42A77A0-2B44-4C08-8BBB-851B22AED6E8", "versionEndExcluding": "10.0.19042.982", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "HTTP Protocol Stack Remote Code Execution Vulnerability"}, {"lang": "es", "value": "Una vulnerabilidad de Ejecuci\u00f3n de C\u00f3digo Remota de HTTP Protocol Stack"}], "id": "CVE-2021-31166", "lastModified": "2025-10-22T00:17:35.357", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "HIGH", "cvssData": {"accessComplexity": "LOW", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "PARTIAL", "baseScore": 7.5, "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P", "version": "2.0"}, "exploitabilityScore": 10.0, "impactScore": 6.4, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "nvd@nist.gov", "type": "Primary", "userInteractionRequired": false}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "secure@microsoft.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "nvd@nist.gov", "type": "Secondary"}]}, "published": "2021-05-11T19:15:09.300", "references": [{"source": "secure@microsoft.com", "tags": ["Third Party Advisory", "VDB Entry"], "url": "http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html"}, {"source": "secure@microsoft.com", "tags": ["Patch", "Vendor Advisory"], "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory", "VDB Entry"], "url": "http://packetstormsecurity.com/files/162722/Microsoft-HTTP-Protocol-Stack-Remote-Code-Execution.html"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch", "Vendor Advisory"], "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31166"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31166"}], "sourceIdentifier": "secure@microsoft.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "nvd@nist.gov", "type": "Primary"}, {"description": [{"lang": "en", "value": "CWE-416"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}