The WPeMatico RSS Feed Fetcher WordPress plugin before 2.8.26 does not sanitize and escape content it retrieves from a user-supplied source before rendering it, which could allow users such as contributors to perform Stored Cross-Site Scripting attacks against higher-privileged users who review the campaign.
https://wpscan.com/vulnerability/6820fac6-3238-4470-a865-677c4442f658/