WP Meta SEO <= 4.5.2 - Missing Authorization in 'startProcess' to Arbitrary Redirect via 'update_link_redirect' task

The WP Meta SEO plugin for WordPress is vulnerable to unauthorized execution of tasks due to a missing capability check on the startProcess function in versions up to, and including, 4.5.2. This makes it possible for authenticated attackers with subscriber-level access to perform tasks reserved for administrators such as post modifications. This vulnerability occurred as a result of the plugin relying on nonce checks as a means of access control, and that nonce being accessible to all authenticated users regardless of role. Attackers could leverage this to redirect victims to an arbitrary location by setting the link_redirect location through the update_link_redirect task.