The LearnPress – WordPress LMS Plugin for Create and Sell Online Courses plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'quantity (REST) / order_comments (checkout)' parameter in all versions up to, and including, 4.4.10 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. With guest checkout enabled the attack is fully unauthenticated; with guest checkout disabled, any Subscriber-level user can exploit both vectors through their own checkout.