{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-83999", "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "state": "PUBLISHED", "assignerShortName": "microsoft", "dateReserved": "2026-09-01T01:16:35.984Z", "datePublished": "2026-09-08T17:14:19.442Z", "dateUpdated": "2026-09-08T18:34:27.877Z"}, "containers": {"cna": {"title": "Windows Resilient File System (ReFS) Deduplication Service Elevation of Privilege Vulnerability", "datePublic": "2026-09-08T14:00:00.000Z", "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.0.26100.0", "versionEndExcluding": "10.0.26100.33438"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_25H2:*:*:*:*:*:*:arm64:*", "versionStartIncluding": "10.0.26200.0", "versionEndExcluding": "10.0.26200.9445"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_24H2:*:*:*:*:*:*:arm64:*", "versionStartIncluding": "10.0.26100.0", "versionEndExcluding": "10.0.26100.9445"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.0.26100.0", "versionEndExcluding": "10.0.26100.33438"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_26H1:*:*:*:*:*:*:x64:*", "versionStartIncluding": "10.0.28000.0", "versionEndExcluding": "10.0.28000.2954"}]}]}], "affected": [{"vendor": "Microsoft", "product": "Windows 11 Version 24H2", "platforms": ["ARM64-based Systems", "x64-based Systems"], "versions": [{"version": "10.0.26100.0", "lessThan": "10.0.26100.9445", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 11 Version 25H2", "platforms": ["ARM64-based Systems", "x64-based Systems"], "versions": [{"version": "10.0.26200.0", "lessThan": "10.0.26200.9445", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows 11 version 26H1", "platforms": ["ARM64-based Systems", "x64-based Systems"], "versions": [{"version": "10.0.28000.0", "lessThan": "10.0.28000.2954", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server 2025", "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.26100.0", "lessThan": "10.0.26100.33438", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Windows Server 2025 (Server Core installation)", "platforms": ["x64-based Systems"], "versions": [{"version": "10.0.26100.0", "lessThan": "10.0.26100.33438", "versionType": "custom", "status": "affected"}]}], "descriptions": [{"value": "Improper link resolution before file access ('link following') in Windows Resilient File System (ReFS) Deduplication Service allows an authorized attacker to elevate privileges locally.", "lang": "en-US"}], "problemTypes": [{"descriptions": [{"description": "CWE-59: Improper Link Resolution Before File Access ('Link Following')", "lang": "en-US", "type": "CWE", "cweId": "CWE-59"}]}], "providerMetadata": {"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "shortName": "microsoft", "dateUpdated": "2026-09-08T18:34:27.877Z"}, "references": [{"name": "Windows Resilient File System (ReFS) Deduplication Service Elevation of Privilege Vulnerability", "tags": ["vendor-advisory", "patch"], "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83999"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en-US", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "baseSeverity": "HIGH", "baseScore": 7, "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C"}}]}}}

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