The eCommerce Product Catalog plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'style' Shortcode Attribute in all versions up to, and including, 3.5.10 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The payload bypasses WordPress's save-time wp_kses_post sanitization because the malicious content is stored inside shortcode brackets with no HTML tags; the tainted HTML output is only generated at render time by the shortcode handler.