monotone before 0.48.1, when configured to allow remote commands, allows remote attackers to cause a denial of service (crash) via an empty argument to the mtn command.

Monotone 0.25 and earlier, when a user creates a file in a directory called "mt", and when checking out that file on a case-insensitive file system such as Windows or Mac OS X, places the file into the "MT" bookkeeping directory, which could allow context-dependent attackers to execute arbitrary Lua programs as the user running monotone.