The Post Slider and Post Carousel with Post Vertical Scrolling Widget WordPress plugin before 3.2.10 does not validate and escape some of its Widget options before outputting them back in a page/post where the block is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks.
https://wpscan.com/vulnerability/b8a50ae9-40c4-42f8-9342-2440d3bc12bb/