CVE-2026-56168: Windows SMB Server Denial of Service Vulnerability

Overview

Severity

Medium (CVSS 6.5)

CVSS Vector

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

Category

Denial of Service

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2026-Jul

Released

2026-07-14

Description

Null pointer dereference in Windows SMB Server allows an authorized attacker to deny service over a network.

Affected Products (15)

Windows

• Windows Server 2022
• 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 Server 2025 (Server Core installation)
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 24H2 for x64-based Systems
• Windows Server 2025
• Windows 11 version 26H1 for x64-based Systems
• Windows 11 Version 26H1 for ARM64-based Systems

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)

• 5099540
• 5099539
• 5099536
• 5101650
• 5095051
• 5101649

Acknowledgments

<a href="https://www.linkedin.com/in/mateusz-g-509241140/">Mateusz Garncarek</a> with <a href="https://digital-missiles.com/">Digital-Missiles</a>, <a href="https://www.linkedin.com/in/mateusz-g-509241140/">Mateusz Garncarek</a> with <a href="https://digital-missiles.com/">Digital-Missiles</a>

Revision History

• 2026-07-14: Information published.