---
id: CVE-2026-50428
title: >-
  Windows Container Isolation FS Filter Driver (unionfs.sys) Information
  Disclosure Vulnerability
summary: >-
  Out-of-bounds read in Windows Container Isolation FS Filter Driver
  (unionfs.sys) allows an authorized attacker to disclose information locally.
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H/E:U/RL:O/RC:C'
cvssSource: cna
cwe:
  - CWE-125
vendor: Microsoft
product: Windows 11 version 26H1
affected:
  - windows_11_version_26h1 >= 10.0.28000.0 < 10.0.28000.2525
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-07-14T19:33:05.245070Z'
published: '2026-07-14'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T22:30:54.402Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-50428'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50428'
    label: >-
      Windows Container Isolation FS Filter Driver (unionfs.sys) Information
      Disclosure Vulnerability
tags:
  - cve.org
epss: 0.00412
epssPercentile: 0.35149
ingestedAt: '2026-09-08T17:06:31.919Z'
---

## Overview

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

## Affected

- `windows_11_version_26h1 >= 10.0.28000.0 < 10.0.28000.2525`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.