sylius/paypal-plugin is a paypal plugin for the Sylius development platform. In affected versions the URL to the payment page done after checkout was created with autoincremented payment id (/pay-with-paypal/{id}) and therefore it was easy to predict. The problem is that the Credit card form has prefilled "credit card holder" field with the Customer's first and last name and hence this can lead to personally identifiable information exposure.

Additionally, the mentioned form did not require authentication. The problem has been patched in Sylius/PayPalPlugin 1.2.4 and 1.3.1. If users are unable to update they can override a sylius_paypal_plugin_pay_with_paypal_form route and change its URL parameters to (for example) {orderToken}/{paymentId}, then override the Sylius\PayPalPlugin\Controller\PayWithPayPalFormAction service, to operate on the payment taken from the repository by these 2 values.

It would also require usage of custom repository method. Additionally, one could override the @SyliusPayPalPlugin/payWithPaypal.html.twig template, to add contingencies: ['SCA_ALWAYS'] line in hostedFields.submit(...) function call (line 421). It would then have to be handled in the function callback.