The Password Protected – Password Protect your WordPress Site, Pages, & WooCommerce Products – Restrict Content, Protect WooCommerce Category and more plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 2.7.7 via the 'password_protected_cookie' function. This makes it possible for unauthenticated attackers to extract sensitive data including all protected site content if the 'Use Transient' setting is enabled.
https://plugins.trac.wordpress.org/changeset/3274358/
https://plugins.trac.wordpress.org/browser/password-protected/trunk/includes/compatibility.php