SEO Metrics <= 1.0.15 - Missing Authorization to Authenticated (Subscriber+) Privilege Escalation

The SEO Metrics plugin for WordPress is vulnerable to Privilege Escalation due to missing authorization checks in both the seo_metrics_handle_connect_button_click() AJAX handler and the seo_metrics_handle_custom_endpoint() function in all versions up to, and including, 1.0.15. Because the AJAX action only verifies a nonce, without checking the caller’s capabilities, a subscriber-level user can retrieve the token and then access the custom endpoint to obtain full administrator cookies.