Block Referer Spam <= 1.1.9.4 - Authenticated (Administrator+) Stored Cross-Site Scripting

The Block Referer Spam plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in versions up to, and including, 1.1.9.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only impacts multi-site installations and installations where unfiltered_html has been disabled.