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.
References10
- plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/…
- plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/…
- plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/…
- plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/…
- plugins.trac.wordpress.org/browser/essential-blocks/trunk/inclu…
- plugins.trac.wordpress.org/browser/essential-blocks/trunk/inclu…
- plugins.trac.wordpress.org/browser/essential-blocks/trunk/inclu…
- plugins.trac.wordpress.org/browser/essential-blocks/trunk/inclu…
- plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&repo…
- www.wordfence.com/threat-intel/vulnerabilities/id/3e7eed9d-2d44…
Metrics
- CVSS 3.1
-
6.4
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N - EPSS — exploit probability
- 0% percentile: 37 · as of 13 November 2026
- CWE
- CWE-79
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.