Privilege escalation in GiveWP donation plugin via donor default role

The GiveWP – Donation Plugin and Fundraising Platform plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 4.19.1 via the `donor_default_user_role` parameter. This is due to the `sanitize_option_donor_default_user_role()` function applying only a narrow literal check against the string `'administrator'` rather than enforcing the plugin's own `give_get_donor_safe_user_roles()` allowlist on save, and due to the `give_core_settings_import_callback()` AJAX handler writing imported JSON directly into the `give_settings` option via `update_option()` without invoking the sanitize filter at all. This makes it possible for authenticated attackers with the GiveWP Manager role (holding the `manage_give_settings` capability) and above to configure donor registration to assign privileged WordPress roles — up to and including Administrator via the import path — to every new donor account created through the platform. Via the settings save path, the Administrator role is blocked but any other elevated role (Editor, Author, etc.) is accepted; via the Tools › Import JSON path, the sanitize filter is bypassed entirely, allowing the Administrator role itself to be stored and subsequently applied to all newly registered donor accounts.