Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-42904
Published: June 11, 2026
Vulnerability identifier: #VU134355
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-42904
CWE-ID: CWE-122
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to escalate privileges on the target system.
The vulnerability exists due to a boundary error in Windows TCP/IP. A remote attacker on the local network can pass specially crafted data to the application, trigger a heap-based buffer overflow and gain elevated privileges on the target system.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-42904
Install updates from vendor's website.
Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7417, 10 22H2 10.0.19045.7417, 10 1607 10.0.14393.9234, 11 23H2 10.0.22631.7219, 11 24H2 10.0.26100.8655, 11 25H2 10.0.26200.8655, 11 26H1 10.0.28000.2269
Windows Server - addressed in versions 2022 10.0.20348.5256, 2025 10.0.26100.8655, 2025 10.0.26100.32995
Windows Server - addressed in versions 2022 10.0.20348.5256, 2025 10.0.26100.8655, 2025 10.0.26100.32995