CVE-2026-121401

A flaw was found in FreeRDP. A malicious or compromised Remote Desktop (RD) Gateway can cause a Denial of Service (DoS) by sending an unexpected extended-authentication packet prior to tunnel authentication. Due to missing verification of the negotiated authentication context, processing this packet triggers a null-pointer dereference that crashes the client application.

This vulnerability is rated as Moderate impact because exploitation results exclusively in a denial of service by terminating the client process, with no compromise of system confidentiality or integrity. Successful exploitation requires an active connection to a malicious or compromised Remote Desktop Gateway that delivers out-of-order authentication packets during tunnel negotiation. In typical Red Hat Enterprise Linux deployments, FreeRDP acts purely as a client, meaning the blast radius is confined to the individual user session.

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.