AVideo has an unauthenticated decrypt oracle leaking any ciphertext

WWBN AVideo is an open source video platform. In versions up to and including 26.0, the API plugin exposes a `decryptString` action without any authentication. Anyone can submit ciphertext and receive plaintext. Ciphertext is issued publicly (e.g., `view/url2Embed.json.php`), so any user can recover protected tokens/metadata. Commit 3fdeecef37bb88967a02ccc9b9acc8da95de1c13 contains a patch.