Use of uninitialized resource in Microsoft Windows and Windows Server - CVE-2026-56190
Published: July 17, 2026
Vulnerability identifier: #VU138119
CSH Severity: High
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-56190
CWE-ID: CWE-908
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to use of uninitialized resource in Windows RDP when handling specially crafted Remote Desktop Protocol traffic. A remote attacker can send specially crafted RDP traffic to execute arbitrary code.
Exploitation requires that Network Level Authentication (NLA) be disabled on the target system.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-56190
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 25H2 10.0.26200.8875, 11 26H1 10.0.28000.2269, 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