Cost Calculator Builder <= 3.6.17 - Missing Authorization to Authenticated (Subscriber+) Sensitive Information Disclosure

The Cost Calculator Builder plugin for WordPress is vulnerable to unauthorized access of sensitive data due to a missing capability check on the `cost-calculator-custom-export-run` AJAX action (handler `CCBExportImport::export_calculators()`) in all versions up to, and including, 3.6.17. The handler only verifies a nonce, but the corresponding `ccb_export_nonce` is broadcast on every wp-admin page (including pages reachable to Subscribers, such as `/wp-admin/profile.php`) by the `ccb_add_admin_nonces` callback hooked to `admin_head`. This makes it possible for authenticated attackers, with Subscriber-level access and above, to export every calculator's full configuration — including stored Stripe secret keys, PayPal client secrets, Razorpay secret keys, webhook secret keys, and reCAPTCHA secret keys.