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Microsoft Security Response CenterCVE-2026-50428

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

Out-of-bounds read in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to disclose information locally.

Read the vendor bulletin Get alerts for Windows
7.1CVSS out of 10High severity
Scope

What the vendor says is affected

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

Versions the vendor lists as fixed

  • 10.0.28000.2525
Next step

What the vendor recommends

Install KB5101649.

Review the complete instructions on the vendor's site
Timeline

When this advisory changed

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

Vulnerabilities

CVEs named in this advisory

CVE-2026-50428View CVSS, KEV, EPSS, and threat context
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