Contextual Related Posts < 3.3.1 - Contributor+ Stored XSS

The plugin 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

1. Insert a "Contextual Related Posts" block, and give it the following additional CSS classes: " onmouseover="alert(1)" style="background:red;"

2. Hover over the block where it's inserted to trigger the XSS