High MSRC-CVE-2026-72971 1 CVE

Windows Container Isolation FS Filter Driver (unionfs.sys) Tampering Vulnerability

Published Aug 11, 2026 · Updated Aug 11, 2026

Vendor: Microsoft

Summary

Impact: Tampering. Microsoft rating: Important. Not known to be exploited, publicly disclosed before the fix — Exploitation Unlikely. Customer action: Required.

Details

Security updates
10.0.28000.2704 — https://support.microsoft.com/help/5121000

Vulnerabilities 1

Medium 5.5

CVE-2026-72971

Windows Container Isolation FS Filter Driver (unionfs.sys) Tampering Vulnerability

Improper link resolution before file access ('link following') in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to perform tampering locally.

Microsoft Windows 11 version 26H1 Windows

Aug 11, 2026

Revision history

2026-08-11 #1
Information published.

References

CVE-2026-72971 Windows Container Isolation FS Filter Driver (unionfs.sys) Tampering Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-72971
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