Support Board <= 3.8.0 - Unauthenticated Authorization Bypass due to Use of Default Secret Key

The Support Board plugin for WordPress is vulnerable to unauthorized access/modification/deletion of data due to use of hardcoded default secrets in the sb_encryption() function in all versions up to, and including, 3.8.0. This makes it possible for unauthenticated attackers to bypass authorization and execute arbitrary AJAX actions defined in the sb_ajax_execute() function. An attacker can use this vulnerability to exploit CVE-2025-4828 and various other functions unauthenticated.