Speed Optimizer < 7.8.5 - Admin+ Stored XSS via DNS Prefetch and Font Preload URL Lists

Description

The plugin does not sanitise or escape some of its settings before outputting them in the head of front-end pages, which could allow high-privilege users such as admins to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in a multisite setup).