Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-56194
Published: July 17, 2026
Vulnerability identifier: #VU138123
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-56194
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to escalate privileges.
The vulnerability exists due to heap-based buffer overflow in Windows Network File System when handling network file system requests. A remote user can send specially crafted network requests to escalate privileges.
Successful exploitation could allow the attacker to obtain SYSTEM privileges.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-56194
Install security update from vendor's website.
Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7548, 10 22H2 10.0.19045.7548, 10 1607 10.0.14393.9339, 10 1809 10.0.17763.9020, 11 24H2 10.0.26100.8875, 11 26H1 10.0.28000.2525
Windows Server - addressed in versions 2012 R2 6.3.9600.23291, 2012 6.2.9200.26226, 2016 10.0.14393.9339, 2019 10.0.17763.9020, 2022 10.0.20348.5386, 2025 10.0.26100.33158
Windows Server - addressed in versions 2012 R2 6.3.9600.23291, 2012 6.2.9200.26226, 2016 10.0.14393.9339, 2019 10.0.17763.9020, 2022 10.0.20348.5386, 2025 10.0.26100.33158