source: http://www.securityfocus.com/bid/6775/info

It has been reported that a directory traversal vulnerability exists in several games using some versions of the Unreal Engine.

It is possible for attackers to traverse outside of the game's installation directory using directory traversal sequences.

If the attacker refers to specific files it may be possible to cause the vulnerable game client to crash.

unreal://\directory\file
unreal://..\..\directory\file