CVE-2026-91955

A flaw was found in FreeRDP. FreeRDP contains a flaw where it fails to validate client-supplied desktop dimensions during the Graphics Command Channel (GCC) negotiation. A remote attacker can exploit this by sending crafted Remote Desktop Protocol (RDP) packets with zero or oversized dimensions. This can lead to division-by-zero or assertion failures, causing the server process to terminate and resulting in a denial of service.

This vulnerability is rated as having an Important severity because an unauthenticated remote attacker can trigger a denial of service against the FreeRDP server component without needing special privileges. In standard Red Hat Enterprise Linux deployments, FreeRDP packages are primarily utilized as client applications, which are unaffected by this defect. The risk is limited to environments exposing FreeRDP server instances or custom listeners to untrusted network traffic.

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.

To reduce exposure, restrict network access to the FreeRDP server to trusted clients only. Configure firewall rules to limit incoming connections to the RDP port (typically 3389) from known and authorized IP addresses or subnets. If the FreeRDP server is not essential, consider disabling the service to prevent exploitation. Any changes to firewall rules or service status may require a service restart to take effect.