There was an argument injection vulnerability in Sourcetree for macOS from version 1.0b2 before version 3.0.0 before version 3.0.0, via Git subrepositories in Mercurial repositories. An attacker with permission to commit to a Mercurial repository linked in Sourcetree for macOS is able to exploit this issue to gain code execution on the system.

For additional details, see the full advisory