Admidio has IDOR in `documents-files.php` `mode=move_save` that lets any folder-uploader exfiltrate files from private folders

Admidio is an open-source user management solution. Prior to version 5.0.10, `modules/documents-files.php` gates state-changing modes by checking that the actor has `hasUploadRight()` on the URL parameter `folder_uuid`. The `move_save` handler then operates on a *separate* URL parameter `file_uuid` and calls `File::moveToFolder($destFolderUUID)`. `File::moveToFolder()` checks the upload right on the destination folder but never on the source folder containing the file. As a result, any user who can upload to any single folder can move any file from any other folder — including private folders to which they have no view rights — into a folder they control, and then download it. Confidentiality is broken (private file contents leak) and integrity is broken (the file is removed from the original location). Version 5.0.10 contains a fix.