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Microsoft Security Response CenterCVE-2026-69617

Windows Resilient File System (ReFS) Elevation of Privilege Vulnerability

HighVendor CVSS 7.0 / 10 1 CVE Published Sep 8, 2026 at 7:00 AM UTC

Summary

Out-of-bounds read in Windows Resilient File System (ReFS) allows an authorized attacker to elevate privileges locally.

Products covered

  • Windows Server 2025 (Server Core installation)

  • Windows Server 2025

  • Windows 11 version 26H1 for x64-based Systems

  • Windows 11 Version 26H1 for ARM64-based Systems

Remediation

Install KB5122871. Install KB5124012.

Vendor-listed fixes

  • 10.0.26100.33438

  • 10.0.28000.2954

CVEs in this advisory 1

Updates

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

  3. Confirmed at the source

    Our collector saw this advisory during a later source check.