Reusable Text Blocks <= 1.5.3 - Author+ Stored Cross-Site Scripting via Shortcode

Description

The plugin does not validate and escape some of its attributes for the text-blocks shortcode before outputting them back into the page, which could allow users with a role of Administrator or higher to perform Stored Cross-Site Scripting attacks, which could be used against high-privilege users such as a superadmin.