RSS Aggregator by Feedzy < 4.1.1 - Contributor+ Stored XSS

The plugin does not validate and escape some of its block options before outputting them back in the page, which could allow users with a role as low as contributor to perform Stored Cross-Site Scripting attacks which could be used against high privilege users such as admins.

PoC

1. Add the Feedzy RSS Feeds Block. 2. Then add the CSS Class to the Block: " onmouseover=“alert(1)” style=“background:red;” 3. Hover the mouse over the content displayed by the block in a page/post to trigger the payload.