GBI To Print <= 1.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'div' Shortcode Attribute

The GBI To Print plugin for WordPress is vulnerable to Stored Cross-Site Scripting in version 1.0 via the 'div' attribute of the 'gbitoprint' shortcode. This is due to insufficient output escaping in the gbi_toprint_shortcode() function, which concatenates the raw shortcode attribute value directly into an HTML attribute without applying esc_attr() or any other sanitization. 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.