CVE-2026-62775: Windows Container Isolation FS Filter Driver (unionfs.sys) Information Disclosure Vulnerability

Overview

Severity

Medium (CVSS 5.5)

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C

Category

Information Disclosure

Exploit Status

Not Exploited

Exploitation Likelihood

Unlikely

Patch Tuesday

2026-Aug

Released

2026-08-11

Description

Incorrect authorization in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to disclose information locally.

FAQ

What type of information could be disclosed by this vulnerability? The type of information that could be disclosed if an attacker successfully exploited this vulnerability includes unauthorized access to the file system, specifically file path information.

Affected Products (2)

Windows

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

Security Updates (1)

• 5121000

Acknowledgments

yhw & txz

Revision History

• 2026-08-11: Information published.