The Call Now Button WordPress plugin before 1.4.7 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).
The Call Now Button WordPress plugin before 1.1.2 does not escape a parameter before outputting it back in an attribute of a hidden input, leading to a Reflected Cross-Site Scripting when the premium is enabled