Heap-based buffer overflow in FreeRDP - #VU137834
Published: July 16, 2026
Vulnerability identifier: #VU137834
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to a heap-based buffer overflow in rail_server_handle_messages() in the server-side RAIL channel handling code when processing a crafted RAIL PDU header with an orderLength smaller than the fixed header length. A remote user can send a specially crafted RDP client message to cause a denial of service.
The issue is triggered when a malicious or compromised RDP client can reach the server-side RAIL channel.
Affected software
FreeRDP
Remediation
Install security update from vendor's website.
FreeRDP - update to 3.29.0