The WP Hello Bar plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'digit_one' and 'digit_two' parameters in all versions up to, and including, 1.02 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
https://wordpress.org/plugins/wp-hello-bar/
https://plugins.trac.wordpress.org/browser/wp-hello-bar/tags/1.02/wp-hello-bar.php#L222
https://plugins.trac.wordpress.org/browser/wp-hello-bar/tags/1.02/wp-hello-bar.php#L214
https://plugins.trac.wordpress.org/browser/wp-hello-bar/tags/1.02/wp-hello-bar.php#L152
https://downloads.wordpress.org/plugin/wp-hello-bar.1.02.zip