There was an argument injection vulnerability in Atlassian Sourcetree for macOS from version 1.2 before version 3.1.1 via filenames in Mercurial repositories. A remote 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.
https://seclists.org/bugtraq/2019/Mar/30
https://jira.atlassian.com/browse/SRCTREE-6391