Buffer overflow in Half Life dedicated server before build 3104 allows remote attackers to execute arbitrary commands via a long rcon command.
https://exchange.xforce.ibmcloud.com/vulnerabilities/5375
http://www.securityfocus.com/bid/1799
http://www.securityfocus.com/archive/1/141060
http://archives.neohapsis.com/archives/bugtraq/2000-10/0409.html
http://archives.neohapsis.com/archives/bugtraq/2000-10/0254.html