A malicious third-party can give a crafted "ssh://..." URL to an unsuspecting victim, and an attempt to visit the URL can result in any program that exists on the victim's machine being executed. Such a URL could be placed in the .gitmodules file of a malicious project, and an unsuspecting victim could be tricked into running "git clone --recurse-submodules" to trigger the vulnerability.

Git before 2.10.5, 2.11.x before 2.11.4, 2.12.x before 2.12.5, 2.13.x before 2.13.6, and 2.14.x before 2.14.2 uses unsafe Perl scripts to support subcommands such as cvsserver, which allows attackers to execute arbitrary OS commands via shell metacharacters in a module name. The vulnerable code is reachable via git-shell even without CVS support.