Bears Backup <= 2.0.0 - Unauthenticated Remote Code Execution

The Bears Backup plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 2.0.0. This is due to the bbackup_ajax_handle() function not having a capability check, nor validating user supplied input passed directly to call_user_func(). This makes it possible for unauthenticated attackers to execute code on the server which can be leverage to inject backdoors or create new administrative user accounts to name a few things. On WordPress sites running the Alone theme versions 7.8.4 and older, this can be chained with CVE-2025-5394 to install the Bears Backup plugin and achieve the same impact.