Atlassian SourceTree v2.5c and prior are affected by a command injection in the handling of the sourcetree:// scheme. It will lead to arbitrary OS command execution with a URL substring of sourcetree://cloneRepo/ext:: or sourcetree://checkoutRef/ext:: followed by the command. The Atlassian ID number is SRCTREE-4632.
Atlassian SourceTree versions 2.5c and below suffer from a command injection vulnerability. This advisory gives a ridiculously small amount of information regarding the issue itself.