WP Express Checkout < 2.2.9 - Admin+ Stored XSS

Description

The plugin does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup). If the 'Admin Dashboard Access Permission' is set to allow low privilege users to access the plugin's dashboard, they could also perform such attack