MSRC-CVE-2026-105509 — Windows Resilient File System (ReFS) Elevation of Privilege Vulnerability

Summary

Impact: Elevation of Privilege. Microsoft rating: Important. Not known to be exploited — Exploitation Unlikely. Customer action: Required.

Details

What privileges could be gained by an attacker who successfully exploited this vulnerability?
An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation of this vulnerability requires an attacker to win a race condition.

Security updates
10.0.28000.3501 — https://support.microsoft.com/help/5132059

Vulnerabilities 1

High 7.0

CVE-2026-105509

Windows Resilient File System (ReFS) Elevation of Privilege Vulnerability

Use after free in Windows Resilient File System (ReFS) allows an authorized attacker to elevate privileges locally.

Microsoft Windows 11 version 26H1 Windows

Nov 10, 2026

Revision history

2026-11-10 #1
Information published.

References

CVE-2026-105509 Windows Resilient File System (ReFS) Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-105509
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss