The Mega Addons For WPBakery Page Builder WordPress plugin before 4.3.0 does not validate and escape some of its shortcode attributes before outputting them back in a page/post where the shortcode is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks.
https://wpscan.com/vulnerability/99389641-ad1e-45c1-a42f-2a010ee22d76