The plugin 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
Add a Brand with an image, and assign it to a Product on the Product Edit page.
[product_brand post_id="PRODUCT_ID" height='" onload=alert(/XSS/)//"']