The Show-Hide / Collapse-Expand WordPress plugin before 1.3.0 does not validate and escape some of its shortcode attributes before outputting them back in the page, which could allow users with a role as low as contributor to perform Stored Cross-Site Scripting attacks which could be used against high privilege users such as admins.
https://wpscan.com/vulnerability/57e528ce-ec8c-4734-8903-926be36f91e7