CVE-2026-42904

Published: Jun 9, 2026Modified: Jun 17, 2026

9.6

Vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploitability: 2.8 / Impact: 6.0

Source: secure@microsoft.com (Secondary)

Description

Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate privileges over an adjacent network.

Affected (16)

Products: Microsoft: Windows 10 21h2, Windows 10 22h2, Windows 11 23h2, Windows 11 24h2, Windows 11 25h2, Windows 11 26h1, Windows Server 2022, Windows Server 2025

8 products

Windows 10 21h2

Windows 10 22h2

Windows 11 23h2

Windows 11 24h2

Windows 11 25h2

Windows 11 26h1

Windows Server 2022

Windows Server 2025

Configuration A

16 vulnerable

Vulnerable Software	Affected Versions
Microsoft Windows 10 21h2	version < 10.0.19044.7417
Microsoft Windows 10 21h2	version < 10.0.19044.7417
Microsoft Windows 10 21h2	version < 10.0.19044.7417
Microsoft Windows 10 22h2	version < 10.0.19045.7417
Microsoft Windows 10 22h2	version < 10.0.19045.7417
Microsoft Windows 10 22h2	version < 10.0.19045.7417
Microsoft Windows 11 23h2	version < 10.0.22631.7219
Microsoft Windows 11 23h2	version < 10.0.22631.7219
Microsoft Windows 11 24h2	version < 10.0.26100.8655
Microsoft Windows 11 24h2	version < 10.0.26100.8655
Microsoft Windows 11 25h2	version < 10.0.26200.8655
Microsoft Windows 11 25h2	version < 10.0.26200.8655
Microsoft Windows 11 26h1	version < 10.0.28000.2269
Microsoft Windows 11 26h1	version < 10.0.28000.2269
Microsoft Windows Server 2022	version < 10.0.20348.5256
Microsoft Windows Server 2025	version < 10.0.26100.32995

Related CWEs

Heap-based Buffer Overflow

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42904

Source: secure@microsoft.com

Vendor Advisory

Timeline

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