Donation Thermometer < 2.1.3 - Admin+ Stored Cross-Site Scripting

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)

PoC

Put the following payload in the Settings > Thermometer > Currency settings: " style=animation-name:rotation onanimationstart=alert(/XSS/)// Save the changes, the XSS will be triggered when accessing the settings again, as well as in the frontend in pages where the [thermometer] is embed