The HandleCrashedAircraft function in aircraft_cmd.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 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."

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 buffer overflows in OpenTTD before 1.1.3 allow remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code via vectors related to (1) NAME, (2) PLYR, (3) CHTS, or (4) AIPL (aka AI config) chunk loading from a savegame.

Multiple buffer overflows in OpenTTD before 1.1.3 allow local users to cause a denial of service (daemon crash) or possibly gain privileges via (1) a crafted BMP file with RLE compression or (2) crafted dimensions in a BMP file.

Multiple off-by-one errors in order_cmd.cpp in OpenTTD before 1.1.3 allow remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code via a crafted CMD_INSERT_ORDER command.

The NetworkSyncCommandQueue function in network/network_command.cpp in OpenTTD before 1.0.3 does not properly clear a pointer in a linked list, which allows remote attackers to cause a denial of service (infinite loop and CPU consumption) via a crafted request, related to the client command queue.

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.