Import and export users and customers <= 2.5.11 - Authenticated (Custom+) Privilege Escalation via Non-Atomic Cron Settings Save

The Import and export users and customers plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 2.5.11 This is due to a non-atomic multi-option write sequence in the `ACUI_Cron::save_settings()` function, which persists `acui_cron_activated`, `acui_cron_configured_by`, `acui_cron_user_id`, and `acui_cron_path_to_file` before reaching the authorization gate that calls `wp_die()` when a non-promoter submits a role. This makes it possible for authenticated attackers holding a custom delegated role with `create_users` but without `promote_users` or `edit_users` to escalate their privileges to Administrator, provided a prior administrator cron-tab save exists and no successful save intervenes before the next unattended cron tick processes the attacker's repointed CSV file.