CyberICT

CVE-2026-83999

Microsoft · Published September 8, 2026

CVSS v3.1

HIGH
Patch availableGet patch

Description

Windows Resilient File System (ReFS) Deduplication Service Elevation of Privilege Vulnerability. Improper link resolution before file access ('link following') in Windows Resilient File System (ReFS) Deduplication Service allows an authorized attacker to elevate privileges locally.

Affected Products

  • Windows Server 2025 (Server Core installation)
  • Windows 11 Version 25H2 for ARM64-based Systems
  • Windows 11 Version 25H2 for x64-based Systems
  • Windows 11 Version 24H2 for ARM64-based Systems

CVSS Vector

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