Magento-lts is a long-term support alternative to Magento Community Edition (CE). This XSS vulnerability affects the design/header/welcome, design/header/logo_src, design/header/logo_src_small, and design/header/logo_alt system configs.They are intended to enable admins to set a text in the two cases, and to define an image url for the other two cases. But because of previously missing escaping allowed to input arbitrary html and as a consequence also arbitrary JavaScript. The problem is patched with Version 20.10.1 or higher.

Magento LTS vulnerable to stored Cross-site Scripting (XSS) in admin system configs