OpenTTD 0.3.5 through 1.1.4 allows remote attackers to cause a denial of service (game pause) by connecting to the server and not finishing the (1) authorization phase or (2) map download, aka a "slow read" attack.
http://www.tt-forums.net/viewtopic.php?f=33&t=58073&hilit=pause#p989303
http://www.openwall.com/lists/oss-security/2012/01/13/8
http://www.openwall.com/lists/oss-security/2012/01/07/2
http://www.debian.org/security/2012/dsa-2524
http://security.openttd.org/en/CVE-2012-0049