The Custom Field Suite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via a meta import in all versions up to, and including, 2.6.4 due to insufficient input sanitization and output escaping on the meta values. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.