{"affected": [{"affectedData": [{"product": ".NET 5.0", "vendor": "Microsoft", "versions": [{"lessThan": "5.0.9", "status": "affected", "version": "5.0.0", "versionType": "custom"}]}, {"product": ".NET Core 2.1", "vendor": "Microsoft", "versions": [{"lessThan": "2.1.30", "status": "affected", "version": "2.1", "versionType": "custom"}]}, {"product": ".NET Core 3.1", "vendor": "Microsoft", "versions": [{"lessThan": "3.1.18", "status": "affected", "version": "3.1", "versionType": "custom"}]}, {"product": "Microsoft Visual Studio 2017 version 15.9 (includes 15.0 - 15.8)", "vendor": "Microsoft", "versions": [{"lessThan": "15.9.38", "status": "affected", "version": "15.9.0", "versionType": "custom"}]}, {"product": "Microsoft Visual Studio 2019 version 16.10 (includes 16.0 - 16.9)", "vendor": "Microsoft", "versions": [{"lessThan": "16.10.5", "status": "affected", "version": "16.10.0", "versionType": "custom"}]}, {"product": "Microsoft Visual Studio 2019 version 16.4 (includes 16.0 - 16.3)", "vendor": "Microsoft", "versions": [{"lessThan": "16.4.25", "status": "affected", "version": "16.0", "versionType": "custom"}]}, {"product": "Microsoft Visual Studio 2019 version 16.7 (includes 16.0 \u2013 16.6)", "vendor": "Microsoft", "versions": [{"lessThan": "16.7.18", "status": "affected", "version": "16.0.0", "versionType": "custom"}]}, {"product": "Microsoft Visual Studio 2019 version 16.9 (includes 16.0 - 16.8)", "vendor": "Microsoft", "versions": [{"lessThan": "16.9.10", "status": "affected", "version": "15.0.0", "versionType": "custom"}]}, {"product": "PowerShell Core 7.0", "vendor": "Microsoft", "versions": [{"lessThan": "7.0.7", "status": "affected", "version": "7.0.0", "versionType": "custom"}]}, {"product": "PowerShell Core 7.1", "vendor": "Microsoft", "versions": [{"lessThan": "7.1.4", "status": "affected", "version": "7.1.0", "versionType": "custom"}]}, {"product": "Visual Studio 2019 for Mac version 8.10", "vendor": "Microsoft", "versions": [{"lessThan": "8.10.7", "status": "affected", "version": "8.1.0", "versionType": "custom"}]}], "source": "secure@microsoft.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*", "matchCriteriaId": "B85CD4C7-D84B-4C54-A604-FC852038A565", "versionEndIncluding": "5.0.8", "versionStartIncluding": "5.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:microsoft:.net_core:*:*:*:*:*:*:*:*", "matchCriteriaId": "FB624437-CB1B-46A2-BF75-30035D99D2EF", "versionEndIncluding": "2.1.28", "versionStartIncluding": "2.1", "vulnerable": true}, {"criteria": "cpe:2.3:a:microsoft:.net_core:*:*:*:*:*:*:*:*", "matchCriteriaId": "6F344BDC-2929-4CEA-8414-E4D07C1F76F0", "versionEndIncluding": "3.1.17", "versionStartIncluding": "3.1", "vulnerable": true}, {"criteria": "cpe:2.3:a:microsoft:powershell_core:*:*:*:*:*:*:*:*", "matchCriteriaId": "BE4005F4-89BB-4597-9070-1137B4CEFC9B", "versionEndExcluding": "7.0.7", "versionStartIncluding": "7.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:microsoft:powershell_core:*:*:*:*:*:*:*:*", "matchCriteriaId": "40F33C0C-7AF0-4B48-828C-00534012D728", "versionEndExcluding": "7.1.4", "versionStartIncluding": "7.1", "vulnerable": true}, {"criteria": "cpe:2.3:a:microsoft:visual_studio_2017:*:*:*:*:*:*:*:*", "matchCriteriaId": "CE03B37D-72FE-4C25-BE62-9C422AEFC80E", "versionEndIncluding": "15.9", "versionStartIncluding": "15.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:microsoft:visual_studio_2019:*:*:*:*:*:*:*:*", "matchCriteriaId": "26472C42-CDB4-4176-B10B-3BF26F5030E3", "versionEndIncluding": "16.10", "versionStartIncluding": "16.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:microsoft:visual_studio_2019:8.10:*:*:*:*:macos:*:*", "matchCriteriaId": "BA547FFE-D557-4612-9840-EEE88ACF53AA", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": ".NET Core and Visual Studio Denial of Service Vulnerability"}, {"lang": "es", "value": "Una Vulnerabilidad de Denegaci\u00f3n de Servicio en .NET Core y Visual Studio"}], "id": "CVE-2021-26423", "lastModified": "2026-08-10T16:17:31.570", "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-2021-26423", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2025-06-04T13:28:43.832819Z", "version": "2.0.3"}}]}, "published": "2021-08-12T18:15:08.537", "references": [{"source": "secure@microsoft.com", "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26423"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch", "Vendor Advisory"], "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26423"}], "sourceIdentifier": "secure@microsoft.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}