Printful Integration for WooCommerce < 2.2.12 - Authenticated (Contributor+) Server-Side Request Forgery

Description

The Printful Integration for WooCommerce plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 2.2.11 via the advanced size chart REST API endpoint. This is due to insufficient validation of user-supplied URLs before passing them to the download_url() function. This makes it possible for authenticated attackers, with Contributor-level access and above, to make web requests to arbitrary locations originating from the web application which can be used to query and modify information from internal services.