The WPB Show Core WordPress plugin before 2.7 does not sanitise and escape a parameter before outputting it back in the page, leading to a Reflected Cross-Site Scripting which could be used against high privilege users such as admin or unauthenticated users
https://wpscan.com/vulnerability/8be4ebcf-2b42-4b88-89a0-2df6dbf00b55/