Windows Fast FAT Driver: Local privilege escalation via race condition

Summary

A race condition (improper synchronization of a shared resource) in the Windows Fast FAT Driver allows an authorized local user to elevate privileges. The attacker needs a low-privileged account on the affected machine and must win a timing race, so the attack complexity is high. Successful exploitation can lead to full control of the system (high confidentiality, integrity and availability impact).

Affected

• Windows 10 Version 1809 (also Windows Server 2019, including Server Core): 10.0.17763.0 to before 10.0.17763.9487
• Windows 10 Version 21H2: 10.0.19044.0 to before 10.0.19044.7846
• Windows 10 Version 22H2: 10.0.19045.0 to before 10.0.19045.7846
• Windows 11 Version 23H2: 10.0.22631.0 to before 10.0.22631.7711
• Windows 11 Version 24H2: 10.0.26100.0 to before 10.0.26100.9974
• Windows 11 Version 25H2: 10.0.26200.0 to before 10.0.26200.9974
• Windows 11 Version 26H1: 10.0.28000.0 to before 10.0.28000.3501
• Windows 11 Version 26H2: 10.0.26300.0 to before 10.0.26300.9974
• Windows Server 2022: 10.0.20348.0 to before 10.0.20348.5870
• Windows Server 2025 (including Server Core): 10.0.26100.0 to before 10.0.26100.33822

Fixed in

• Install the Microsoft security update for November 2026 (Patch Tuesday, published 10 November 2026) or later cumulative update for the affected Windows version, as listed in the MSRC advisory.

Workaround

Unknown.

Exploitation

• CISA SSVC assessment: exploitation none, not automatable, total technical impact.
• No public proof of concept or in-the-wild exploitation known at the time of writing.

Our recommendation

• Patch affected Windows clients and servers with the November 2026 cumulative update as part of the normal patch cycle; treat as a priority, not an emergency, unless exploitation is reported.
• Check the MSRC advisory for the exact fixed build numbers and KB articles for each Windows version.
• Limit local interactive logons on shared, multi-user or terminal servers.
• Restrict or monitor the use of FAT-formatted removable media such as USB sticks and SD cards.
• Check NVD and the CISA KEV catalogue for updates.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• Microsoft Security Update Guide: CVE-2026-113751 msrc.microsoft.com
• CVE Record CVE-2026-113751 (CVE Program) www.cve.org

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 09:04.