The vulnerability is explicitly tied to line 9 in index.js, which corresponds to the exec() call within the execute function. This function accepts arbitrary command strings and executes them without sanitization, making it a direct OS command injection vector. Functions like clip() and parseAudio() that use execute() inherit this vulnerability when building their command strings with user-controlled parameters (e.g., inputFilePath/outputFilePath), but the root cause is the unsanitized exec() call in execute(). The PoC demonstrates exploitation via execute('touch JHU'), confirming this path.