Float to Top Button <= 2.3.6 - Admin+ Stored Cross-Site Scripting

The plugin does not 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)

PoC

Put the following payload in the “Text for the button” or “URL of a custom “Top of Page” image” settings of the plugin and save: "autofocus onfocus=alert(/XSS/)// The XSS will be triggered when accessing the settings page again