The vulnerability fundamentally stems from insecure path resolution logic in the static file serving component. While the exact code isn't available, the nature of directory traversal vulnerabilities in Node.js static servers strongly indicates that:

1. The handler accepts raw URL paths
2. Uses them in path resolution functions without normalization checks
3. Fails to verify the resolved path remains within the web root This pattern matches the described attack vector where '/../../../../etc/passwd' is accepted as a valid path. The high confidence comes from the vulnerability's universal manifestation pattern in similar packages and the explicit PoC demonstration.