CVE-2026-33647 — Unrestricted File Upload in Avideo

WWBN AVideo is an open source video platform. In versions up to and including 26.0, the `ImageGallery::saveFile()` method validates uploaded file content using `finfo` MIME type detection but derives the saved filename extension from the user-supplied original filename without an allowlist check. An attacker can upload a polyglot file (valid JPEG magic bytes followed by PHP code) with a `.php` extension. The MIME check passes, but the file is saved as an executable `.php` file in a web-accessibl…