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

Summary

Improper access control in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to elevate privileges locally.

Remediation

1. Inventory every Microsoft Windows 11 version 23H2 deployment, including staging.
2. Upgrade Microsoft Windows 11 version 23H2 to the fixed version for your release line, listed under Affected versions.
3. Confirm the running version after the upgrade.

References

• Patchhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-102202