OpenTTD 0.6.0 through 1.2.1 does not properly validate requests to clear a water tile, which allows remote attackers to cause a denial of service (NULL pointer dereference and server crash) via a certain sequence of steps related to "the water/coast aspect of tiles which also have railtracks on one half."
https://exchange.xforce.ibmcloud.com/vulnerabilities/77266
http://www.securityfocus.com/bid/54720
http://www.openwall.com/lists/oss-security/2012/07/31/5
http://www.openwall.com/lists/oss-security/2012/07/28/7
http://www.openwall.com/lists/oss-security/2012/07/27/5
http://vcs.openttd.org/svn/changeset/24439
http://security.openttd.org/en/CVE-2012-3436
http://secunia.com/advisories/50042
http://lists.opensuse.org/opensuse-updates/2012-08/msg00043.html