CVE-2021-26866

{"containers": {"cna": {"title": "Windows Update Service Elevation of Privilege Vulnerability", "datePublic": "2021-03-09T16:00:00.000Z", "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*", "versionStartIncluding": "10.0.0", "versionEndExcluding": "10.0.17134.2087"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*", "versionStartIncluding": "10.0.17763.0", "versionEndExcluding": "10.0.17763.1817"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:arm64:*", "versionStartIncluding": "10.0.0", "versionEndExcluding": "10.0.17763.1817"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.0.17763.0", "versionEndExcluding": "10.0.17763.1817"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.0.17763.0", "versionEndExcluding": "10.0.17763.1817"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1909:*:*:*:*:*:*:x86:*", "versionStartIncluding": "10.0.0", "versionEndExcluding": "10.0.18363.1440"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_1909:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.0.0", "versionEndExcluding": "10.0.18363.1440"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*", "versionStartIncluding": "10.0.0", "versionEndExcluding": "10.0.19043.867"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2004:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.0.0", "versionEndExcluding": "10.0.19043.867"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_20H2:*:*:*:*:*:*:x86:*", "versionStartIncluding": "10.0.0", "versionEndExcluding": "10.0.19043.867"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_20H2:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.0.0", "versionEndExcluding": "10.0.19043.867"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:x86:*", "versionStartIncluding": "10.0.10240.0", "versionEndExcluding": "10.0.10240.18874"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*", "versionStartIncluding": "10.0.14393.0", "versionEndExcluding": "10.0.14393.4283"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.0.14393.0", "versionEndExcluding": "10.0.14393.4283"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.0.14393.0", "versionEndExcluding": "10.0.14393.4283"}]}]}], "affected": [{"vendor": "Microsoft", "product": "Windows 10 Version 1507", "platforms": ["32-bit Systems", "x64-based Systems"], "versions": [{"version": "10.0.10240.0", "lessThan": "10.0.10240.18874", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 10 Version 1607", "platforms": ["32-bit Systems", "x64-based Systems"], "versions": [{"version": "10.0.14393.0", "lessThan": "10.0.14393.4283", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 10 Version 1803", "platforms": ["32-bit Systems", "ARM64-based Systems", "x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.17134.2087", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 10 Version 1809", "platforms": ["32-bit Systems", "x64-based Systems"], "versions": [{"version": "10.0.17763.0", "lessThan": "10.0.17763.1817", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 10 Version 1809", "platforms": ["ARM64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.17763.1817", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 10 Version 1909", "platforms": ["32-bit Systems", "ARM64-based Systems", "x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.18363.1440", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 10 Version 2004", "platforms": ["32-bit Systems", "ARM64-based Systems", "x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19043.867", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 10 Version 20H2", "platforms": ["32-bit Systems", "ARM64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19043.867", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server 2016", "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.14393.0", "lessThan": "10.0.14393.4283", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server 2016 (Server Core installation)", "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.14393.0", "lessThan": "10.0.14393.4283", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server 2019", "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.17763.0", "lessThan": "10.0.17763.1817", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server 2019 (Server Core installation)", "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.17763.0", "lessThan": "10.0.17763.1817", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server version 2004", "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19043.867", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server version 20H2", "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.19043.867", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server, version 1909 (Server Core installation)", "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.0", "lessThan": "10.0.18363.1440", "versionType": "custom", "status": "affected"}]}], "descriptions": [{"value": "Windows Update Service Elevation of Privilege Vulnerability", "lang": "en-US"}], "problemTypes": [{"descriptions": [{"description": "Elevation of Privilege", "lang": "en-US", "type": "Impact"}]}], "providerMetadata": {"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "shortName": "microsoft", "dateUpdated": "2026-08-19T16:30:20.830Z"}, "references": [{"name": "Windows Update Service Elevation of Privilege Vulnerability", "tags": ["vendor-advisory", "patch"], "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26866"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en-US", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "baseSeverity": "HIGH", "baseScore": 7.1, "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H/E:U/RL:O/RC:C"}}]}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-03T20:33:41.155Z"}, "title": "CVE Program Container", "references": [{"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26866"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://www.zerodayinitiative.com/advisories/ZDI-21-286/"}]}]}, "cveMetadata": {"assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "assignerShortName": "microsoft", "cveId": "CVE-2021-26866", "datePublished": "2021-03-11T15:38:37.000Z", "dateReserved": "2021-02-08T00:00:00.000Z", "dateUpdated": "2026-08-19T16:30:20.830Z", "state": "PUBLISHED"}, "dataType": "CVE_RECORD", "dataVersion": "5.2"}

{}

{"affected": [{"affectedData": [{"platforms": ["32-bit Systems", "x64-based Systems"], "product": "Windows 10 Version 1507", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.10240.18874", "status": "affected", "version": "10.0.10240.0", "versionType": "custom"}]}, {"platforms": ["32-bit Systems", "x64-based Systems"], "product": "Windows 10 Version 1607", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.14393.4283", "status": "affected", "version": "10.0.14393.0", "versionType": "custom"}]}, {"platforms": ["32-bit Systems", "ARM64-based Systems", "x64-based Systems"], "product": "Windows 10 Version 1803", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.17134.2087", "status": "affected", "version": "10.0.0", "versionType": "custom"}]}, {"platforms": ["32-bit Systems", "x64-based Systems"], "product": "Windows 10 Version 1809", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.17763.1817", "status": "affected", "version": "10.0.17763.0", "versionType": "custom"}]}, {"platforms": ["ARM64-based Systems"], "product": "Windows 10 Version 1809", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.17763.1817", "status": "affected", "version": "10.0.0", "versionType": "custom"}]}, {"platforms": ["32-bit Systems", "ARM64-based Systems", "x64-based Systems"], "product": "Windows 10 Version 1909", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.18363.1440", "status": "affected", "version": "10.0.0", "versionType": "custom"}]}, {"platforms": ["32-bit Systems", "ARM64-based Systems", "x64-based Systems"], "product": "Windows 10 Version 2004", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.19043.867", "status": "affected", "version": "10.0.0", "versionType": "custom"}]}, {"platforms": ["32-bit Systems", "ARM64-based Systems"], "product": "Windows 10 Version 20H2", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.19043.867", "status": "affected", "version": "10.0.0", "versionType": "custom"}]}, {"platforms": ["x64-based Systems"], "product": "Windows Server 2016", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.14393.4283", "status": "affected", "version": "10.0.14393.0", "versionType": "custom"}]}, {"platforms": ["x64-based Systems"], "product": "Windows Server 2016 (Server Core installation)", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.14393.4283", "status": "affected", "version": "10.0.14393.0", "versionType": "custom"}]}, {"platforms": ["x64-based Systems"], "product": "Windows Server 2019", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.17763.1817", "status": "affected", "version": "10.0.17763.0", "versionType": "custom"}]}, {"platforms": ["x64-based Systems"], "product": "Windows Server 2019 (Server Core installation)", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.17763.1817", "status": "affected", "version": "10.0.17763.0", "versionType": "custom"}]}, {"platforms": ["x64-based Systems"], "product": "Windows Server version 2004", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.19043.867", "status": "affected", "version": "10.0.0", "versionType": "custom"}]}, {"platforms": ["x64-based Systems"], "product": "Windows Server version 20H2", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.19043.867", "status": "affected", "version": "10.0.0", "versionType": "custom"}]}, {"platforms": ["x64-based Systems"], "product": "Windows Server, version 1909 (Server Core installation)", "vendor": "Microsoft", "versions": [{"lessThan": "10.0.18363.1440", "status": "affected", "version": "10.0.0", "versionType": "custom"}]}], "source": "secure@microsoft.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:*:*", "matchCriteriaId": "21540673-614A-4D40-8BD7-3F07723803B0", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:*:*", "matchCriteriaId": "9E2C378B-1507-4C81-82F6-9F599616845A", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_10:1607:*:*:*:*:*:*:*", "matchCriteriaId": "E01A4CCA-4C43-46E0-90E6-3E4DBFBACD64", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_10:1803:*:*:*:*:*:*:*", "matchCriteriaId": "7CB85C75-4D35-480E-843D-60579EC75FCB", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:*:*", "matchCriteriaId": "6B8F3DD2-A145-4AF1-8545-CC42892DA3D1", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:*:*", "matchCriteriaId": "E9273B95-20ED-4547-B0A8-95AD15B30372", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:*:*", "matchCriteriaId": "AAE74AF3-C559-4645-A6C0-25C3D647AAC8", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*", "matchCriteriaId": "041FF8BA-0B12-4A1F-B4BF-9C4F33B7C1E7", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2016:20h2:*:*:*:*:*:*:*", "matchCriteriaId": "4A190388-AA82-4504-9D5A-624F23268C9F", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2016:1909:*:*:*:*:*:*:*", "matchCriteriaId": "C253A63F-03AB-41CB-A03A-B2674DEA98AA", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:*", "matchCriteriaId": "0B60D940-80C7-49F0-8F4E-3F99AC15FA82", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*", "matchCriteriaId": "DB79EE26-FC32-417D-A49C-A1A63165A968", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Windows Update Service Elevation of Privilege Vulnerability"}, {"lang": "es", "value": "Una Vulnerabilidad de Elevaci\u00f3n de Privilegios del Update Service de Windows"}], "id": "CVE-2021-26866", "lastModified": "2026-08-19T17:17:40.377", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "LOW", "cvssData": {"accessComplexity": "LOW", "accessVector": "LOCAL", "authentication": "NONE", "availabilityImpact": "PARTIAL", "baseScore": 3.6, "confidentialityImpact": "NONE", "integrityImpact": "PARTIAL", "vectorString": "AV:L/AC:L/Au:N/C:N/I:P/A:P", "version": "2.0"}, "exploitabilityScore": 3.9, "impactScore": 4.9, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "nvd@nist.gov", "type": "Primary", "userInteractionRequired": false}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.1, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.2, "source": "secure@microsoft.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 6.1, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 4.2, "source": "nvd@nist.gov", "type": "Secondary"}]}, "published": "2021-03-11T16:15:14.440", "references": [{"source": "secure@microsoft.com", "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26866"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch", "Vendor Advisory"], "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26866"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory", "VDB Entry"], "url": "https://www.zerodayinitiative.com/advisories/ZDI-21-286/"}], "sourceIdentifier": "secure@microsoft.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-59"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{}

{}