Is WP Blockade safe? Known vulnerabilities and latest version

The WP Blockade plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'shortcode' parameter in all versions up to and including 0.9.14. This is due to insufficient input sanitization and output escaping in the render_shortcode_preview() function. The function receives user input from $_GET['shortcode'], passes it through stripslashes() without any sanitization, and then outputs it directly via echo do_shortcode($shortcode) on line 393. When the input is not a valid WordPress shortcode (e.g., an HTML tag with JavaScript event handlers), do_shortcode() returns it unchanged, and it is reflected into the page without escaping. The endpoint is registered via admin_post_ (not admin_post_nopriv_), meaning it requires the user to be logged in with at minimum a Subscriber-level account. There is no nonce verification or additional capability check. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject arbitrary web scripts in pages that will execute if they can successfully trick a user into performing an action such as clicking a link.

The WP Blockade plugin for WordPress is vulnerable to Missing Authorization in all versions up to and including 0.9.14. The plugin registers an admin_post action hook 'wp-blockade-shortcode-render' that maps to the render_shortcode_preview() function. This function lacks any capability check (current_user_can()) and nonce verification, allowing any authenticated user to execute arbitrary WordPress shortcodes. The function takes a user-supplied 'shortcode' parameter from $_GET, passes it through stripslashes(), and directly executes it via do_shortcode(). This makes it possible for authenticated attackers, with Subscriber-level access and above, to execute arbitrary shortcodes, which could lead to information disclosure, privilege escalation, or other impacts depending on what shortcodes are registered on the site (e.g., shortcodes from other plugins that display sensitive data, perform actions, or include files).