The vulnerability occurs in the command construction at line 59 and subsequent execution via child_process.exec. The code builds a Java command string (JSCoverCommand) that directly incorporates the user-controlled 'source' argument without any sanitization. When this unsanitized input is passed to exec(), it enables arbitrary command execution through shell injection techniques. The combination of user input interpolation in system commands and lack of input validation/sanitization matches the CWE-78 pattern.