The reCAPTCHA WordPress plugin through 1.6 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).
https://wpscan.com/vulnerability/fa23bd68-69f3-440e-902c-a3bb6c8a40b8