What is CVE-2026-72971?

CVE-2026-72971 is a security advisory published by Microsoft Security Response Center (MSRC) with High severity. Windows Container Isolation FS Filter Driver (unionfs.sys) Tampering Vulnerability

Which CVE IDs does CVE-2026-72971 cover?

CVE-2026-72971 covers the following CVE IDs: CVE-2026-72971. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of CVE-2026-72971?

CVE-2026-72971 has a CVSS v3 base score of 5.5, published by Microsoft Security Response Center (MSRC).

Which products are affected by CVE-2026-72971?

CVE-2026-72971 affects 2 products, including: Windows 11 Version 26H1 for ARM64-based Systems; Windows 11 version 26H1 for x64-based Systems.

CVE-2026-72971HighCVSS 5.5

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

Vendor

Microsoft Security Response Center (MSRC)

Published

August 14, 2026

Last Modified

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🔗 CVE IDs covered (1)

CVE-2026-72971 →

📋 Description

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.

🎯 Affected products2

Windows 11 Version 26H1 for ARM64-based Systems
Windows 11 version 26H1 for x64-based Systems

✅ Remediation

KB5121000 (Security Update) — fixed build 10.0.28000.2704

🔗 References (3)

advisoryhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-72971
patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5121000
referencehttps://support.microsoft.com/help/5121000