{"affected": [{"affectedData": [{"platforms": ["x64-based Systems"], "product": "Windows Server 2008 R2 Service Pack 1", "vendor": "Microsoft", "versions": [{"lessThan": "6.1.7601.24566", "status": "affected", "version": "6.1.7601.0", "versionType": "custom"}]}, {"platforms": ["x64-based Systems"], "product": "Windows Server 2008 R2 Service Pack 1 (Server Core installation)", "vendor": "Microsoft", "versions": [{"lessThan": "6.1.7601.24566", "status": "affected", "version": "6.1.7601.0", "versionType": "custom"}]}, {"platforms": ["32-bit Systems", "x64-based Systems"], "product": "Windows Server 2008 Service Pack 2", "vendor": "Microsoft", "versions": [{"lessThan": "6.0.6003.21070", "status": "affected", "version": "6.0.6003.0", "versionType": "custom"}]}, {"platforms": ["32-bit Systems", "x64-based Systems"], "product": "Windows Server 2008 Service Pack 2 (Server Core installation)", "vendor": "Microsoft", "versions": [{"lessThan": "6.0.6003.21070", "status": "affected", "version": 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"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_server_2008:r2:sp1:*:*:*:*:x64:*", "matchCriteriaId": "AF07A81D-12E5-4B1D-BFF9-C8D08C32FF4F", "vulnerable": true}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2008:sp2:*:*:*:*:*:*:*", "matchCriteriaId": "66CAFDB7-9D41-4E67-AB83-5EB104551FF5", "vulnerable": true}, {"criteria": 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"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 DNS Server Denial of Service Vulnerability"}, {"lang": "es", "value": "Una Vulnerabilidad de Denegaci\u00f3n de Servicio del Servidor DNS de Windows. Este ID de CVE es diferente de CVE-2021-26896"}], "id": "CVE-2021-27063", "lastModified": "2026-08-19T17:17:50.193", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "MEDIUM", "cvssData": {"accessComplexity": "LOW", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "PARTIAL", "baseScore": 5.0, "confidentialityImpact": "NONE", "integrityImpact": "NONE", "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P", "version": "2.0"}, "exploitabilityScore": 10.0, "impactScore": 2.9, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "nvd@nist.gov", "type": "Primary", "userInteractionRequired": false}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "secure@microsoft.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2021-27063", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2024-02-27T16:26:41.277144Z", "version": "2.0.3"}}]}, "published": "2021-03-11T16:15:17.847", "references": [{"source": "secure@microsoft.com", "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-27063"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch", "Vendor Advisory"], "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27063"}], "sourceIdentifier": "secure@microsoft.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}