Heap-based buffer overflow in Windows and Windows Server - CVE-2026-54990
Published: July 17, 2026
Vulnerability identifier: #VU137934
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2026-54990
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Microsoft
Affected software:
Windows
Windows Server
Windows
Windows Server
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to heap-based buffer overflow in Remote Desktop Client when handling responses from a malicious RDP server. A remote attacker can send specially crafted responses to execute arbitrary code.
User interaction is required to establish a connection to a malicious RDP server.
How to mitigate CVE-2026-54990
Install security update from vendor's website.