PDF Invoices & Packing Slips for WooCommerce <= 5.16.4 - Unauthenticated Stored Cross-Site Scripting via Billing First Name / Last Name / Company / Customer Note fields at guest checkout

The PDF Invoices & Packing Slips for WooCommerce plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'billing_address.first_name / last_name / company, customer_note' parameter in all versions up to, and including, 5.16.4 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. This is an incomplete fix for CVE-2026-92244: the wp_kses() allow-list introduced in 5.16.2 correctly blocks raw-tag payloads but is bypassed by entity-encoded payloads (e.g., &lt;img onerror=…&gt;) that contain no literal angle-bracket characters and are therefore passed through unmodified before the trailing decode rematerializes them.