The advisory explicitly states the vulnerability occurs at fs.readFile in index.js due to missing path sanitization. The function takes user-controlled path input (from HTTP requests) and passes it directly to filesystem operations without validation(). This matches the classic directory traversal pattern where attacker-controlled paths with '../' sequences can access arbitrary files. Multiple sources (GitHub Advisory, NVD, Snyk) confirm the root cause is unsanitized fs.readFile usage in this file.