{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-21255", "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "state": "PUBLISHED", "assignerShortName": "microsoft", "dateReserved": "2025-12-11T21:02:05.736Z", "datePublished": "2026-02-10T17:51:38.926Z", "dateUpdated": "2026-02-10T20:38:52.224Z"}, "containers": {"cna": {"title": "Windows Hyper-V Security Feature Bypass Vulnerability", "datePublic": "2026-02-10T08:00:00.000Z", "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_26H1:*:*:*:*:*:*:arm64:*", "versionStartIncluding": "10.0.28000.0", "versionEndExcluding": "10.0.28000.1575"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_26H1:*:*:*:*:*:*:x64:*", "versionStartIncluding": "10.0.28000.0", "versionEndExcluding": "10.0.28000.1575"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*", 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Improper Access Control", "lang": "en-US", "type": "CWE", "cweId": "CWE-284"}]}], "providerMetadata": {"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "shortName": "microsoft", "dateUpdated": "2026-02-10T20:38:52.224Z"}, "references": [{"name": "Windows Hyper-V Security Feature Bypass Vulnerability", "tags": ["vendor-advisory", "patch"], "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21255"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en-US", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "baseSeverity": "HIGH", "baseScore": 8.8, "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C"}}]}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "Improper access control in Windows Hyper-V allows an authorized attacker to bypass a security feature locally."}], "id": "CVE-2026-21255", "lastModified": "2026-02-10T18:16:27.167", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.0, "impactScore": 6.0, "source": "secure@microsoft.com", "type": "Primary"}]}, "published": "2026-02-10T18:16:27.167", "references": [{"source": "secure@microsoft.com", "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21255"}], "sourceIdentifier": "secure@microsoft.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-284"}], "source": "secure@microsoft.com", "type": "Primary"}]}

{}

{}