CVE-2026-83999 Windows Resilient File System (ReFS) Deduplication Service Elevation of Privilege Vulnerability

{
  "id": "857c34c909f88ebd2a7d530e982b6121b562128e3ac28f9cc51ee5cca1943f9e",
  "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83999",
  "method": "llm",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-83999 Windows Resilient File System (ReFS) Deduplication Service Elevation of Privilege Vulnerability",
    "summary": "An improper link-resolution issue in the Windows ReFS Deduplication Service may let an authorized attacker elevate privileges locally.",
    "evidence": "Improper link resolution before file access ('link following') in Windows Resilient File System (ReFS) Deduplication Service allows an authorized attacker to elevate privileges locally.",
    "products": [
      {
        "name": {
          "value": "Windows Resilient File System (ReFS) Deduplication Service",
          "evidence": "Windows Resilient File System (ReFS) Deduplication Service"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "fixed_cves": [],
    "related_cves": [
      {
        "value": "CVE-2026-83999",
        "evidence": "CVE-2026-83999 Windows Resilient File System (ReFS) Deduplication Service Elevation of Privilege Vulnerability"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "official-microsoft-security-updates",
  "document_id": 26755,
  "published_at": "2026-09-08T14:00:00+00:00"
}