NextGEN Gallery <= 3.28 is vulnerable to Cross-Site Request Forgery (CSRF)

The NextGEN Gallery plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 3.28. This is due to missing or incorrect nonce validation on the 'ajax_set_post_thumbnail' and 'createNewThumb' functions. This makes it possible for unauthenticated attackers to create and set thumbnails on posts via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.