Windows Storage Spaces Controller: Local privilege escalation via TOCTOU race condition

Summary

A time-of-check time-of-use (TOCTOU) race condition in the Windows Storage Spaces Controller allows a locally authenticated user to elevate privileges. An attacker needs a low-privileged account or code execution on the host first, and the race is not reliable (high attack complexity). A successful attack can fully compromise confidentiality, integrity and availability of the affected system.

Affected

• Windows 10 Version 1607 (10.0.14393.0 to before 10.0.14393.9688)
• Windows 10 Version 1809 (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 2016 incl. Server Core (10.0.14393.0 to before 10.0.14393.9688)
• Windows Server 2019 incl. Server Core (10.0.17763.0 to before 10.0.17763.9487)
• Windows Server 2022 (10.0.20348.0 to before 10.0.20348.5870)

Fixed in

Install the November 2026 security update for the affected Windows build. Fixed builds are the first builds not listed as affected in the CVE record, for example 10.0.14393.9688 (Windows 10 1607 / Server 2016), 10.0.17763.9487 (1809 / Server 2019) and 10.0.20348.5870 (Server 2022). Verify the exact builds in the MSRC advisory.

Workaround

Unknown.

Exploitation

• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• No evidence of in-the-wild exploitation or public proof of concept found in the sources reviewed.
• Vendor CVSS temporal rating: Exploit Code Maturity Unproven.

Our recommendation

• Install the November 2026 cumulative update on all affected Windows hosts, prioritising multi-user systems, file servers and Storage Spaces hosts.
• Check which Windows builds are in use and replace unsupported releases such as Windows 10 1607 and 1809 where possible.
• Limit local logon rights and remove unneeded accounts on sensitive hosts.
• Monitor for unexpected privilege changes and suspicious local processes on affected systems.

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-2026-119851 msrc.microsoft.com
• CVE Record CVE-2026-119851 (CVE.org) www.cve.org
• Strix: CVE-2026-119851 www.strix.ai

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, 08:42.