The Header Footer Script Adder – Insert Code in Header, Body & Footer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'asm_code' Snippet Meta in all versions up to, and including, 2.1 due to insufficient input sanitization and output 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.