CVE-2026-18358

A flaw was found in gnome-remote-desktop as shipped in Red Hat Enterprise Linux. When the daemon is running in system mode with RDP enabled, the incoming connection handler bypasses the connection throttler, allowing an unauthenticated remote attacker to open many parallel pre-authentication connections to the RDP listener. This can accumulate accepted sockets and pending routing-token operations until timeout, exhausting resources and preventing legitimate users from establishing RDP sessions. This issue does not affect the upstream version.

This vulnerability only affects deployments where gnome-remote-desktop is explicitly configured to run in system mode with the RDP port reachable from untrusted networks. The default user-session mode is not affected. The Moderate rather than Important severity rating reflects that exploitation requires a non-default configuration (system-mode RDP must be explicitly enabled and the listener must be network-accessible), which significantly limits the practical attack surface.

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.

If system-mode RDP is not required, disable it. If it must remain enabled, restrict the RDP listener (default port 3389) to trusted hosts or management networks using host-based firewall rules.