CVE-2026-4658

Vulnerability Description

The Essential Blocks – Page Builder Gutenberg Blocks, Patterns & Templates plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the className, classHook, and blockId attributes in the Add to Cart block (essential-blocks/add-to-cart) in all versions up to, and including, 6.0.4. This is due to insufficient output escaping in the render_callback() function where these attributes are placed into class and data-id HTML attributes using raw sprintf() and implode() without esc_attr() escaping. While the outer wrapper div uses get_block_wrapper_attributes() which properly escapes, the inner divs do not. 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.

CVSS Score

Related Weaknesses (CWE)

References

• https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/
• https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/
• https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/
• https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/
• https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Block
• https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Block
• https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Block
• https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Block
• https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&new
• https://www.wordfence.com/threat-intel/vulnerabilities/id/3e7eed9d-2d44-4951-b66