The Code Embed plugin for WordPress is vulnerable to Stored Cross-Site Scripting via custom field meta values in all versions up to, and including, 2.5.1. This is due to the plugin's sanitization function sec_check_post_fields() only running on the save_post hook, while WordPress allows custom fields to be added via the wp_ajax_add_meta AJAX endpoint without triggering save_post. The ce_filter() function then outputs these unsanitized meta values directly into page content without 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.