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 when the unfiltered_html capability is disallowed (for example in multisite setup)
Put the following payload in any of the settings accepting a string (ie "This string in the page content will be replaced by the tag cloud", "Category prefix" etc): "><svg/onload=alert(/XSS/)>