Published: 10 August 2017
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.
From the Ubuntu security team
Brian Neel, Joern Schneeweisz, and Jeff King discovered that Git did not properly handle host names in 'ssh://' URLs. A remote attacker could use this to construct a git repository that when accessed could run arbitrary code with the privileges of the user.
CVSS 3 base score: 8.8