Easy Google Fonts <= 2.0.4 - Authenticated (Author+) Stored Cross-Site Scripting via control_selectors Meta Field

Description

The Easy Google Fonts plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the control_selectors meta field in all versions up to, and including, 2.0.4. This is due to the plugin registering the control_selectors meta field with show_in_rest enabled but without a sanitize_callback, and subsequently outputting this unsanitized data directly into <style> tags on the frontend without proper escaping. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.