CVE-2026-4658The 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 th…
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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
- 6.4 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Deferred
- Record last updated
- Jun 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
No affected products are listed yet.
References
- https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/Blocks/AddToCart.php#L118
- https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/Blocks/AddToCart.php#L120
- https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/Blocks/AddToCart.php#L65
- https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/Blocks/AddToCart.php#L66
- https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L118
- https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L120
- https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L65
- https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L66
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&new=3516287%40essential-blocks%2Ftags%2F6.1.0%2Fincludes%2FBlocks%2FAddToCart.php&old=3178777%40essential-blocks%2Ftrunk%2Fincludes%2FBlocks%2FAddToCart.php
- https://www.wordfence.com/threat-intel/vulnerabilities/id/3e7eed9d-2d44-4951-b66b-7d8995ca617d?source=cve
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.