Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-85856
Published: October 14, 2026
Vulnerability identifier: #VU155199
CSH Severity: Low
CVSS v4: 7.5 [CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-85856
CWE-ID: CWE-122
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user on the local network to execute arbitrary code.
The vulnerability exists due to heap-based buffer overflow in Windows Internet Connection Sharing (ICS) when handling interactions over an adjacent network. A remote user on the local network can exploit the buffer overflow over that network to execute arbitrary code.
Successful exploitation requires a deep understanding of the system and depends on factors such as the environment, system configuration, and additional security measures.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-85856
Install security update from vendor's website.
Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7807, 10 1607 10.0.14393.9612, 10 1809 10.0.17763.9376, 11 23H2 10.0.22631.7652, 11 24H2 10.0.26100.9711, 11 25H2 10.0.26200.9711, 11 26H1 10.0.28000.3231
Windows Server - addressed in versions 2012 R2 6.3.9600.23470, 2012 6.2.9200.26434, 2016 10.0.14393.9612, 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650
Windows Server - addressed in versions 2012 R2 6.3.9600.23470, 2012 6.2.9200.26434, 2016 10.0.14393.9612, 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650