CVE-2026-97787

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

State: Published
Severity: 7.0 High
Published: Oct 13, 2026
Updated: Oct 31, 2026
Reserved: Sep 25, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	7.0 High	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C	microsoft

Weaknesses

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Affected Products

Product	Versions
Windows 11 version 23H2Microsoft	10.0.22631.0 to before 10.0.22631.7652Affected
Windows 11 Version 23H2Microsoft	10.0.22631.0 to before 10.0.22631.7652Affected
Windows 11 Version 24H2Microsoft	10.0.26100.0 to before 10.0.26100.9711Affected
Windows 11 Version 25H2Microsoft	10.0.26200.0 to before 10.0.26200.9711Affected
Windows 11 version 26H1Microsoft	10.0.28000.0 to before 10.0.28000.3231Affected
Windows 11 Version 26H2Microsoft	10.0.26300.0 to before 10.0.26300.9711Affected
Windows Server 2022Microsoft	10.0.20348.0 to before 10.0.20348.5761Affected
Windows Server 2025Microsoft	10.0.26100.0 to before 10.0.26100.33650Affected
Windows Server 2025 (Server Core installation)Microsoft	10.0.26100.0 to before 10.0.26100.33650Affected

References

Windows Container Isolation FS Filter Driver (unionfs.sys) Elevation of Privilege Vulnerabilityvendor-advisorypatch

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