Windows Fast FAT File System Driver Information Disclosure Vulnerability
CVE-2026-70277
Summary
Double free in Windows Autopilot allows an authorized attacker to elevate privileges locally.
Products covered
Windows 11 Version 25H2 for ARM64-based Systems
Windows 11 Version 25H2 for x64-based Systems
Windows 11 Version 24H2 for ARM64-based Systems
Windows 11 Version 24H2 for x64-based Systems
Windows 11 version 26H1 for x64-based Systems
Windows 11 Version 26H1 for ARM64-based Systems
Remediation
Install KB5121003. Install KB5120994. Install KB5121000.
Vendor-listed fixes
10.0.26200.9168
10.0.26200.9106
10.0.26100.9168
10.0.26100.9106
10.0.28000.2704
CVEs in this advisory 1
Update history
What changed in later vendor updates
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- The vendor changed its remediation guidance.
Updates
- Published by Microsoft Security Response Center
The publication date reported by the vendor.
- Added to SecurityAlert
We collected the advisory from the official source.
- Confirmed at the source
Our collector saw this advisory during a later source check.