MSRC-CVE-2026-102202 — Windows Container Isolation FS Filter Driver (unionfs.sys) Elevation of Privilege Vulnerability

Summary

Impact: Elevation of Privilege. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

What privileges could be gained by an attacker who successfully exploited this vulnerability?
An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

Security updates
10.0.20348.5761 — https://support.microsoft.com/help/5126655
10.0.28000.3231 — https://support.microsoft.com/help/5127646
10.0.22631.7652 — https://support.microsoft.com/help/5126653
10.0.26100.9711 — https://support.microsoft.com/help/5127648
10.0.26100.33650 — https://support.microsoft.com/help/5126646

Vulnerabilities 1

High 7.8

CVE-2026-102202

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

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

Microsoft Windows Server 2022 Windows Server 2025 Windows Server 2025 (Server Core installation) Windows

Oct 13, 2026

Revision history

2026-10-13 #1
Information published.

References

CVE-2026-102202 Windows Container Isolation FS Filter Driver (unionfs.sys) Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-102202
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss