CVE-2026-78455: Xbox Information Disclosure Vulnerability

Overview

Severity

Medium (CVSS 4.3)

CVSS Vector

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

Category

Information Disclosure

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2026-Sep

Released

2026-09-08

Description

Out-of-bounds read in Xbox allows an unauthorized attacker to disclose information with a physical attack.

FAQ

What type of information could be disclosed by this vulnerability? Exploiting this vulnerability could allow the disclosure of certain kernel memory content.

Affected Products (22)

Windows

• Windows 10 Version 1809 for 32-bit Systems
• Windows 10 Version 1809 for x64-based Systems
• Windows Server 2019
• Windows Server 2019 (Server Core installation)
• Windows 10 Version 21H2 for 32-bit Systems
• Windows 10 Version 21H2 for ARM64-based Systems
• Windows 10 Version 21H2 for x64-based Systems
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 23H2 for ARM64-based Systems
• Windows 11 Version 23H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 24H2 for x64-based Systems
• Windows 11 version 26H1 for x64-based Systems
• Windows 11 Version 26H1 for ARM64-based Systems
• Windows 10 Version 1607 for 32-bit Systems
• Windows 10 Version 1607 for x64-based Systems
• Windows Server 2016
• Windows Server 2016 (Server Core installation)

ESU

• Windows 10 Version 22H2 for x64-based Systems
• Windows 10 Version 22H2 for ARM64-based Systems
• Windows 10 Version 22H2 for 32-bit Systems

Security Updates (6)

• 5122876
• 5122878
• 5124008
• 5122880
• 5124012
• 5123099

Acknowledgments

<a href="https://www.linkedin.com/in/jaemin-kim-b99503278/">Jmini</a>

Revision History

• 2026-09-08: Information published.