The Motors – Car Dealership & Classified Listings plugin for WordPress is vulnerable to Payment Bypass via insecure user meta update in all versions up to, and including, 1.4.103 This is due to the stm_save_user_extra_fields() function updating sensitive user meta fields from POST data without verifying that the current user should have permission to modify those fields. The function hooks into the 'personal_options_update' action and only checks current_user_can('edit_user', $user_id), which passes for any user editing their own profile. This makes it possible for authenticated attackers, with Subscriber-level access and above, to set their stm_payment_status to 'completed', bypassing the PayPal payment verification and gaining access to paid Dealer membership features without completing any transaction.