The Memory Usage plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 3.98. This is due to missing nonce validation in the wpmemory_install_plugin() function. This makes it possible for unauthenticated attackers to silently install one of the several whitelisted plugins via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
https://wordpress.org/plugins/wp-memory/#developers
https://plugins.trac.wordpress.org/changeset/3333316
https://plugins.trac.wordpress.org/browser/wp-memory/tags/3.98/wpmemory.php#L376