whisperX REST API: SSRF in download_from_url() — URL validation happens after HTTP request, extension bypass via .mp3

The whisperX API is a tool for enhancing and analyzing audio content. From 0.3.1 to 0.5.0, FileService.download_from_url() in app/services/file_service.py calls requests.get(url) with zero URL validation. The file extension check occurs AFTER the HTTP request is already made, and can be bypassed by appending .mp3 to any internal URL. The /speech-to-text-url endpoint is unauthenticated. This vulnerability is fixed in 0.6.0.