Improper Neutralization of Special Elements used in a Command ('Command Injection')
The package ungit before 1.5.20 are vulnerable to Remote Code Execution (RCE) via argument injection. The issue occurs when calling the /api/fetch endpoint. User controlled values (remote and ref) are passed to the git fetch command. By injecting some git options it was possible to get arbitrary command execution.
CWE-77 - Command Injection
A command injection attack involves injecting an operating system command through the data input, which gets executed on the host operating system with the privileges of the victimized application. The impact of a command injection attack may range from loss of data confidentiality and integrity to unauthorized remote access to the hosting system. The attack may cause serious data breaches and system takeover.