The PDF Invoices & Packing Slips for WooCommerce plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Billing First Name / Last Name / Company Fields in all versions up to, and including, 5.16.1 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 sanitizetextfield() and wcclean() do not strip entity-encoded strings containing no literal '<' character, allowing unauthenticated guest-checkout orders to plant the malicious content.

Shop manager PHP Object Injection in WooCommerce PDF Invoices & Packing Slips < 5.9.0 versions.

Missing Authorization vulnerability in WP Overnight WooCommerce PDF Invoices & Packing Slips woocommerce-pdf-invoices-packing-slips allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects WooCommerce PDF Invoices & Packing Slips: from n/a through <= 3.8.6.