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CVE-2026-4658

Gutenberg Essential Blocks <= 6.0.4 - Authenticated (Contributor+) Stored Cross-Site Scripting via Block Attributes

Published: May 2, 2026Updated: May 5, 2026 Sources: CVE List NVDCWE-79
NVD MITRE
6.4CVSSMEDIUM
EPSS Score
0.3%
Top 78.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

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 Vector Breakdown

AV:NAC:LPR:LUI:NS:CC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-79

Affected Products

Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patternswpdevteam
On-premCMS Plugin
Web & CMS Plugins / wordpress-plugin
wpdevteamcommercialWeb & CMS Pluginsaka wpdev team, wpdevteam.com

Attack Graph

Products CVE Techniques Tactics

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Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

https://www.wordfence.com/threat-intel/vulnerabilities/id/3e7eed9d-2d44-4951-b66b-7d8995ca617d?source=cve
wordfence.com
https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L118
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/Blocks/AddToCart.php#L118
plugins.trac.wordpress.org
and 7 more references View all →

Timeline

Published
May 2, 2026
Last Updated
May 5, 2026

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