tagDiv Composer <= 5.4.5 - Authenticated (Contributor+) Stored Cross-Site Scripting

Summary

The tagDiv Composer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the vc_raw_html shortcode in all versions up to and including 5.4.5. This is due to insufficient input sanitization and output escaping in the vc_raw_html::render() method, which base64-decodes shortcode content (after a strip_tags() that is bypassed because the encoded payload contains no tags on save) and concatenates the result directly into the page HTML. Because WordPress's save-time wp_kses_post() filter only sees the inert base64 text inside a normal shortcode bracket and does not decode it, the dangerous tags survive into post_content and are emitted unescaped at render time. 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 (for example, when an Editor or Administrator previews the pending post).