The Payment Page | Payment Form for Stripe plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'pricing_plan_select_text_font_family' parameter in all versions up to, and including, 1.4.6 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
https://plugins.trac.wordpress.org/browser/payment-page/trunk/app/PaymentForm.php#L310
https://plugins.trac.wordpress.org/browser/payment-page/tags/1.4.6/app/PaymentForm.php#L310