MSRC-CVE-2026-62772 — 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 Unlikely. 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
10.0.28000.2704 — https://support.microsoft.com/help/5121000

Vulnerabilities 1

High 7.8

CVE-2026-62772

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

Heap-based buffer overflow in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to elevate privileges locally.

Microsoft Windows 11 version 26H1 Windows

Aug 11, 2026

Revision history

2026-09-15 #2
Updated an acknowledgement. This is an informational change only.
2026-08-11 #1
Information published.

References

CVE-2026-62772 Windows Container Isolation FS Filter Driver (unionfs.sys) Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62772
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