SiteSEO – SEO Simplified <= 1.2.7 - Authenticated (Contributor+) Stored Cross-Site Scripting via Broken Regex Expression

The SiteSEO – SEO Simplified plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the broken preg_replace expression in all versions up to, and including, 1.2.7 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.