The HandleCrashedAircraft function in aircraftcmd.cpp in OpenTTD 0.3.6 through 1.3.2 allows remote attackers to cause a denial of service (out-of-bounds read and crash) by crashing an aircraft outside of the map.

OpenTTD before 1.0.1 does not properly validate index values of certain items, which allows remote authenticated users to cause a denial of service (daemon crash) or possibly execute arbitrary code via a crafted in-game command.

OpenTTD before 1.0.1 allows remote attackers to cause a denial of service (file-descriptor exhaustion and daemon crash) by performing incomplete downloads of the map.

OpenTTD before 1.0.1 accepts a company password for authentication in response to a request for the server password, which allows remote authenticated users to bypass intended access restrictions or cause a denial of service (daemon crash) by sending a company password packet.

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.

Multiple use-after-free vulnerabilities in OpenTTD 1.0.x before 1.0.5 allow (1) remote attackers to cause a denial of service (invalid write and daemon crash) by abruptly disconnecting during transmission of the map from the server, related to network/networkserver.cpp; (2) remote attackers to cause a denial of service (invalid read and daemon crash) by abruptly disconnecting, related to network/networkserver.cpp; and (3) remote servers to cause a denial of service (invalid read and application crash) by forcing a disconnection during the join process, related to network/network.cpp.

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."