The WP EasyCart plugin for WordPress is vulnerable to privilege escalation in versions up to, and including, 5.9.3. This is due to the ec_ajax_save_page_default_options() AJAX handler iterating over every $_POST key and passing it directly into update_option() without any allowlist, while gating the handler only on 'manage_options' OR the plugin's custom 'wpec_manager' capability. The plugin's built-in 'wpec_store_manager' role holds 'wpec_manager' but not 'manage_options', and the required nonce is emitted on frontend product/category templates that render for any user with 'wpec_manager'.
This makes it possible for authenticated attackers, with Store Manager-level access and above, to elevate their privileges to administrator by updating arbitrary WordPress options such as default_role='administrator' and users_can_register='1', then self-registering a new account that is assigned the administrator role.
Attack Parameters
Impact Assessment
CVSS Vector v3.1