WPUpper Share Buttons < 3.43 - Admin+ Stored XSS

The plugin does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup).

1. Go to the settings of the plugin and enter the following payload in the input box: 123" onmouseenter=alert(/XSS/) "
2. Save the changes and refresh or re-enter the page and move the mouse over the input box to get the XSS trigger.