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OpenAdvisories
High · 7.0 CVE-2026-97787 EUVD-2026-100309GHSA-6x7p-x5cg-8hh8

Windows Container Isolation FS Filter Driver (unionfs.sys) Elevation of Privilege Vulnerability

Published Oct 13, 2026 · Updated Nov 10, 2026 · Assigned by microsoft

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to elevate privileges locally.

Affected products

VendorProductAffectedFixed
Microsoft Windows 11 version 23H2 10.0.22631.0 – < 10.0.22631.7652 10.0.22631.7652
Microsoft Windows 11 Version 24H2 10.0.26100.0 – < 10.0.26100.9711 10.0.26100.9711
Microsoft Windows 11 Version 25H2 10.0.26200.0 – < 10.0.26200.9711 10.0.26200.9711
Microsoft Windows 11 version 26H1 10.0.28000.0 – < 10.0.28000.3231 10.0.28000.3231
Microsoft Windows 11 Version 26H2 10.0.26300.0 – < 10.0.26300.9711 10.0.26300.9711
Microsoft Windows Server 2022 10.0.20348.0 – < 10.0.20348.5761 10.0.20348.5761
Microsoft Windows Server 2025 10.0.26100.0 – < 10.0.26100.33650 10.0.26100.33650
Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.0 – < 10.0.26100.33650 10.0.26100.33650

Advisories 2

References