A flaw was found in the gnome-remote-desktop package. The gnome-remote-desktop system daemon performs inadequate validation of session agents using D-Bus methods related to transitioning a client connection from the login screen to the user session. As a result, the system RDP TLS certificate and key can be exposed to unauthorized users. This flaw allows a malicious user on the system to take control of the RDP client connection during the login screen-to-user session transition.
Credits
Red Hat would like to thank Matthias Gerstner (SUSE) for reporting this issue.