mosrai 是做什么的？
Use when testing apps that accept media uploads and process them with ffmpeg (audio transcription, video processing, image conversion). If the upload endpoint does not validate file magic bytes and ffmpeg is invoked without protocol restrictions, an HLS playlist with file:// segment URLs achieves cross-user file read, bypassing all application-level ACLs. Triggers - "media upload", "audio processing", "ffmpeg", "transcription", "file upload", "HLS", "m3u8", "file read", "LFI via media", "cross-u