CVE-2026-121398

A flaw was found in FreeRDP. A malicious Remote Desktop Protocol (RDP) server can cause a Denial of Service (DoS) by crashing the proxy service during session termination. When the dynamic channel dump module is enabled, transmitting dynamic channel data while a client disconnects triggers a multi-thread synchronization flaw where released memory is accessed, causing the proxy process to terminate.

Red Hat Product Security rates this vulnerability as Moderate because successful exploitation results solely in a denial of service of the proxy process without integrity or confidentiality impact. In typical Red Hat enterprise environments, FreeRDP is primarily deployed as client-side tools and libraries rather than an active proxy service, and the channel dumping module is not enabled by default. Furthermore, triggering the condition requires an untrusted backend RDP server and precise race timing during concurrent session termination.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.