The Qi Blocks plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 1.4.3. This is due to the plugin storing arbitrary CSS styles submitted via the `qi-blocks/v1/update-styles` REST API endpoint without proper sanitization in the `update_global_styles_callback()` function. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary CSS, which can be used to perform actions such as hiding content, overlaying fake UI elements, or exfiltrating sensitive information via CSS injection techniques.