The Heateor Login – Social Login Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'Heateor_Facebook_Login' shortcode in all versions up to, and including, 1.1.9 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
https://plugins.trac.wordpress.org/browser/heateor-login/tags/1.1.9/shortcode.php#L24