The Essential Blocks WordPress plugin before 4.7.0 does not validate and escape some of its block 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/f2b8f092-4fc0-4edc-ba0f-d4312c2e5dec/