The WP Composer – The Easiest Page Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'pbwp_raw_shortcode' shortcode in all versions up to, and including, 1.0.5. This is due to the shortcode handler decoding Base64-encoded content and outputting it directly without any sanitization or 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. The Base64 encoding allows the payload to bypass WordPress's KSES content filtering at save time, since the encoded string contains no harmful HTML characters.