The remote host is missing an update to x11-xserver-utils announced via advisory USN-1107-1.
Details follow:
Sebastian Krahmer discovered that the xrdb utility incorrectly filtered crafted hostnames. An attacker could use this flaw with a malicious DHCP server or with a remote xdmcp login and execute arbitrary code, resulting in root privilege escalation.
Solution: The problem can be corrected by upgrading your system to the following package versions: