The CP Contact Form with PayPal plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.3.52. This is due to missing or incorrect nonce validation on the cp_contact_form_paypal_check_init_actions() function. This makes it possible for unauthenticated attackers to add discount codes via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.