The WebToffee WooCommerce PDF Invoices, Packing Slips, Delivery Notes & Shipping Labels plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 4.9.8 via the getimagesrcinbase64 function. This makes it possible for authenticated attackers, with subscriber-level access and above, to read the contents of arbitrary files on the server, which can contain sensitive information. The base64-encoded file contents are embedded into the cached invoice HTML and served directly to the attacker via the plugin's own Print/Download invoice endpoints, which require only a valid nonce and access key.