CVE-2026-21240

{"id": "CVE-2026-21240", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-21240", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-02-11T04:55:45.175017Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "secure@microsoft.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.8}, {"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.0, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.0}]}, "affected": [{"source": "secure@microsoft.com", "affectedData": [{"vendor": "Microsoft", "product": "Windows 10 Version 1809", "versions": [{"status": "affected", "version": "10.0.17763.0", "lessThan": "10.0.17763.8389", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 10 Version 21H2", "versions": [{"status": "affected", "version": "10.0.19044.0", "lessThan": "10.0.19044.6937", "versionType": "custom"}], "platforms": ["32-bit Systems", "ARM64-based Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 10 Version 22H2", "versions": [{"status": "affected", "version": "10.0.19045.0", "lessThan": "10.0.19045.6937", "versionType": "custom"}], "platforms": ["32-bit Systems", "ARM64-based Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 11 version 22H3", "versions": [{"status": "affected", "version": "10.0.22631.0", "lessThan": "10.0.22631.6649", "versionType": "custom"}], "platforms": ["ARM64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 11 Version 23H2", "versions": [{"status": "affected", "version": "10.0.22631.0", "lessThan": "10.0.22631.6649", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 11 Version 24H2", "versions": [{"status": "affected", "version": "10.0.26100.0", "lessThan": "10.0.26100.7840", "versionType": "custom"}], "platforms": ["ARM64-based Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 11 Version 25H2", "versions": [{"status": "affected", "version": "10.0.26200.0", "lessThan": "10.0.26200.7840", "versionType": "custom"}]}, {"vendor": "Microsoft", "product": "Windows 11 version 26H1", "versions": [{"status": "affected", "version": "10.0.28000.0", "lessThan": "10.0.28000.1575", "versionType": "custom"}], "platforms": ["ARM64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 11 Version 26H1", "versions": [{"status": "affected", "version": "10.0.28000.0", "lessThan": "10.0.28000.1575", "versionType": "custom"}]}, {"vendor": "Microsoft", "product": "Windows Server 2019", "versions": [{"status": "affected", "version": "10.0.17763.0", "lessThan": "10.0.17763.8389", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows Server 2019 (Server Core installation)", "versions": [{"status": "affected", "version": "10.0.17763.0", "lessThan": "10.0.17763.8389", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows Server 2022", "versions": [{"status": "affected", "version": "10.0.20348.0", "lessThan": "10.0.20348.4773", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows Server 2022, 23H2 Edition (Server Core installation)", "versions": [{"status": "affected", "version": "10.0.25398.0", "lessThan": "10.0.25398.2149", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows Server 2025", "versions": [{"status": "affected", "version": "10.0.26100.0", "lessThan": "10.0.26100.32370", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows Server 2025 (Server Core installation)", "versions": [{"status": "affected", "version": "10.0.26100.0", "lessThan": "10.0.26100.32370", "versionType": "custom"}], "platforms": ["x64-based Systems"]}]}], "published": "2026-02-10T18:16:24.963", "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21240", "tags": ["Vendor Advisory"], "source": "secure@microsoft.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "secure@microsoft.com", "description": [{"lang": "en", "value": "CWE-367"}]}], "descriptions": [{"lang": "en", "value": "Time-of-check time-of-use (toctou) race condition in Windows HTTP.sys allows an authorized attacker to elevate privileges locally."}, {"lang": "es", "value": "Una condici\u00f3n de carrera de tiempo de verificaci\u00f3n tiempo de uso (TOCTOU) en Windows HTTP.sys permite a un atacante autorizado elevar privilegios localmente."}], "lastModified": "2026-06-17T10:18:20.483", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*", "vulnerable": true, "matchCriteriaId": "C09C54DA-6AB0-4696-A2F2-C11CFC292EA9", "versionEndExcluding": "10.0.17763.8389"}, {"criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*", "vulnerable": true, "matchCriteriaId": "369B4E41-3895-4CB7-BD37-D2E4A4D52FB9", 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