Gutenberg Essential Blocks <= 6.0.4 - Authenticated (Contributor+) Stored Cross-Site Scripting via Block Attributes
| CVE | CVE-2026-4658 |
|---|---|
| CVSS | 6.4 (Medium) |
| Publicly Published | May 1, 2026 |
| Last Updated | May 2, 2026 |
| Researchers |
Jack Pas (Dark.)
- Black Lantern Security
normaandersonfrank |
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.
Learn more about Cross-Site Scripting vulnerabilities and how to prevent them.
References
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
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Vulnerability Details for Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns
| Software Type | Plugin |
|---|---|
| Software Slug | essential-blocks (view on wordpress.org) |
| Patched? | Yes |
| Remediation | Update to version 6.1.0, or a newer patched version |
| Affected Version |
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| Patched Version |
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Recent vulnerabilities in Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns
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