Ubercartβs PayPal Website Payments Standard integration exposes a path for completed orders without properly checking that the order is valid for the current user. In the event that the order has already been processed for checkout, this can result in duplicate actions taking place inadvertently. Furthermore, if the checkout completion message has been modified to include order details, information disclosure can happen.
The Ubercart order management was also affected by a minor cross-site request forgery vulnerability.
Drupal core is not affected. If you do not use the contributed Ubercart module, there is nothing you need to do.
Upgrade to the latest version: