Printcart Store - Web to Print Product Designer for WooCommerce (PCDesigner) <= 2.9.1 - Unauthenticated Arbitrary File Upload to Remote Code Execution via nbdesigner_copy_image_from_url

The Printcart Store (PCDesigner / NB Designer) plugin for WooCommerce is vulnerable to unauthenticated arbitrary file upload leading to remote code execution in all versions up to, and including, 2.9.1 The nbdesigner_copy_image_from_url AJAX action is registered for logged-out callers (wp_ajax_nopriv_), and its Google Drive branch rebuilds the destination filename from the raw, attacker-supplied gapi[name] parameter — bypassing the jpg/jpeg/png/gif allow-list applied on the other branch — and writes the fetched bytes to a web-accessible directory (wp-content/uploads/nbdesigner/temp/). This makes it possible for unauthenticated attackers to write a .php file to a web-served, PHP-executing location and, by supplying their own Google Drive file and OAuth token as the content source, execute arbitrary code on the server. The required save-design nonce is handed to anonymous callers by the nbd_check_use_logged_in endpoint, so it presents no barrier.

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Printcart Store 2.9.2 closes this, and updating the plugin is the step that ends it.

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