Soldat game server 1.4.2 and earlier, and dedicated server 2.6.2 and earlier, allows remote attackers to cause a denial of service (client lockout) via a series of UDP join packets from a spoofed IP address, which triggers temporary blacklisting of this IP address.
https://exchange.xforce.ibmcloud.com/vulnerabilities/36232
http://www.securityfocus.com/bid/25426
http://www.securityfocus.com/archive/1/477624/100/0/threaded