The JetFormBuilder — Dynamic Blocks Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the '<form field mapped to a post meta key, e.g. lst_cost>' parameter in all versions up to, and including, 3.6.8 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Exploitation requires the target site to have configured a public Insert Post form writing to a post meta key and a Calculated Field whose formula references that key via the %META::key% macro, after which a single unauthenticated POST is sufficient to persist the payload.