WP Ultimate CSV Importer < 8.1 - Missing Authorization to Authenticated (Subscriber+) Remote Code Execution via 'MappedFields' Parameter

Description

The WP Ultimate CSV Importer – WordPress Import & Export for CSV, XML & Excel plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 8.0.1 via the 'MappedFields' parameter. This is due to missing capability checks on the AJAX handlers for install_addon, saveMappedFields, and StartImport, combined with the plugin nonce being exposed to any authenticated user who can load an admin page, allowing a Subscriber to install the Import WooCommerce add-on, persist attacker-controlled PHP expressions in the MappedFields parameter, and trigger evaluation via eval() in ImportHelpers::get_meta_values(). This makes it possible for authenticated attackers, with subscriber-level access and above, to execute code on the server.