OpenMage magento-lts before 20.18.2 and 21.0.0-beta1 before 21.0.0-beta3 serves RSS feeds with a text/html content type and does not escape feed entry data, leading to stored cross-site scripting. An unauthenticated guest can submit a product review with script in the nickname, title or text that executes when an administrator opens the pending-reviews feed, enabling admin account takeover.
CWE-79