The Paytium: Mollie payment forms & donations WordPress plugin before 4.3.7 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).
https://wpscan.com/vulnerability/8ec76242-717d-4d2d-9c0f-3056cd7c2c90