WooCommerce <= 5.1.3 - Authenticated (Admin+) Stored Cross-Site Scripting

The WooCommerce plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'Additional tax classes' field when the tax functionality of WooCommerce is enabled in versions up to, and including, 5.1.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers with administrative privileges to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.