Checkout for PayPal < 1.0.14 - Contributor+ Stored XSS

The plugin does not validate and escape some of its shortcode attributes before outputting them back in the page, which could allow users with a role as low as contributor to perform Stored Cross-Site Scripting attacks

PoC

As a contributor, put the following shortcode in a page/post [checkout_for_paypal amount=‘1’ item_description=‘“; alert(/XSS/); return ;”’] The XSS will be triggered when viewing/previewing the page/post