Windows Fast FAT File System Driver Information Disclosure Vulnerability
CVE-2026-70277
Summary
Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service over a network.
Products covered
Windows 10 Version 1809 for 32-bit Systems
Windows 10 Version 1809 for x64-based Systems
Windows Server 2019
Windows Server 2019 (Server Core installation)
Windows Server 2022
Windows Server 2022 (Server Core installation)
Windows 10 Version 21H2 for 32-bit Systems
Windows 10 Version 21H2 for ARM64-based Systems
Show 22 more products
Windows 10 Version 21H2 for x64-based Systems
Windows 10 Version 22H2 for x64-based Systems
Windows 10 Version 22H2 for ARM64-based Systems
Windows 10 Version 22H2 for 32-bit Systems
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 23H2 for ARM64-based Systems
Windows 11 Version 23H2 for x64-based Systems
Windows 11 Version 24H2 for ARM64-based Systems
Windows 11 Version 24H2 for x64-based Systems
Windows Server 2025
Windows 11 version 26H1 for x64-based Systems
Windows 11 Version 26H1 for ARM64-based Systems
Windows 10 Version 1607 for 32-bit Systems
Windows 10 Version 1607 for x64-based Systems
Windows Server 2016
Windows Server 2016 (Server Core installation)
Windows Server 2012
Windows Server 2012 (Server Core installation)
Windows Server 2012 R2
Windows Server 2012 R2 (Server Core installation)
Remediation
Install KB5120238. Install KB5120242. Install KB5120229. Install KB5120249. Install KB5120233. Install KB5120228. Install KB5121003. Install KB5120994. Install KB5120240. Install KB5121000. Install KB5120418. Install KB5120386. Install KB5120385.
Vendor-listed fixes
10.0.17763.9121
10.0.20348.5499
10.0.20348.5440
10.0.19044.7663
10.0.19045.7663
10.0.26100.33296
10.0.26100.33222
10.0.26200.9168
Show 8 more fixes
10.0.26200.9106
10.0.22631.7517
10.0.26100.9168
10.0.26100.9106
10.0.28000.2704
10.0.14393.9418
6.2.9200.26280
6.3.9600.23338
CVEs in this advisory 1
Update history
What changed in later vendor updates
SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.
- 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.