CVE-2026-33723: AVideo Vulnerable to SQL Injection in Subscribe Endpoint via Unsanitized user_id Parameter in subscribe.php

WWBN AVideo is an open source video platform. In versions up to and including 26.0, the `Subscribe::save()` method in `objects/subscribe.php` concatenates the `$this->users_id` property directly into an INSERT SQL query without sanitization or parameterized binding. This property originates from `$_POST['user_id']` in both `subscribe.json.php` and `subscribeNotify.json.php`. An authenticated attacker can inject arbitrary SQL to extract sensitive data from any database table, including password hashes, API keys, and encryption salts. Commit 36dfae22059fbd66fd34bbc5568a838fc0efd66c contains a patch.