Punnel <= 1.3.1 - Missing Authorization to Authenticated (Subscriber+) Settings Update via 'punnel_save_config' AJAX Action

The Punnel – Landing Page Builder plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 1.3.1. The save_config() function, which handles the 'punnel_save_config' AJAX action, lacks any capability check (current_user_can()) and nonce verification. This makes it possible for authenticated attackers, with Subscriber-level access and above, to overwrite the plugin's entire configuration including the API key via a POST request to admin-ajax.php. Once the API key is known (because the attacker set it), the attacker can use the plugin's public API endpoint (sniff_requests() at /?punnel_api=1) — which only validates requests by comparing a POST token against the stored api_key — to create, update, or delete arbitrary posts, pages, and products on the site.