PDF Invoices & Packing Slips for WooCommerce < 5.16.2 - Unauthenticated Stored XSS via Billing First Name / Last Name / Company Fields

Description

The plugin is vulnerable to Stored Cross-Site Scripting via the Billing First Name / Last Name / Company fields 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. The payload survives initial storage because WooCommerce's sanitize_text_field() and wc_clean() do not strip entity-encoded strings containing no literal '<' character, allowing unauthenticated guest-checkout orders to plant the malicious content.