The Easy Forms for Mailchimp WordPress plugin through 6.8.10 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Cross-Site Scripting attacks even when unfiltered_html is disallowed
The Easy Forms for Mailchimp WordPress plugin before 6.8.9 does not sanitise and escape some of its from parameters, 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)
The Easy Forms for Mailchimp WordPress plugin before 6.8.9 does not sanitise and escape a parameter before outputting it back in the page when the debug option is enabled, leading to a Reflected Cross-Site Scripting which could be used against high privilege users such as admin.