Paypal Payment Shortcode <= 1.01 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'buttom_image' Shortcode Attribute

The Paypal Payment Shortcode plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'buttom_image' parameter of the [paypal-shortcode] shortcode in all versions up to, and including, 1.01 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.