Unreal Tournament 2004 (UT2004) 3369 and earlier allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a certain sequence of malformed packets.
https://exchange.xforce.ibmcloud.com/vulnerabilities/44107
http://www.vupen.com/english/advisories/2008/2259/references
http://www.securityfocus.com/bid/30427
http://www.securityfocus.com/archive/1/494935/100/0/threaded
http://secunia.com/advisories/31266