WordPress security changelog
MEDIUM CVE-2026-4658 Deferred

Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns: Cross-site scripting

Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns is affected by cross-site scripting. Exploitation requires at least contributor-level access. Injected script can execute in the affected site's origin when the vulnerable output is viewed. The published affected range is <= 6.0.4.

CVE / CNA score 6.4 CVSS 3.1 · security@wordfence.com
NVD score Pending NVD has not published its own CVSS assessment.
Component
Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns
Plugin slug
essential-blocks
Affected
<= 6.0.4
Safe version
> 6.0.4
Published
May 02, 2026
Weakness
CWE-79 — Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

This CVE was published May 02, 2026 and is one of 31 known issues for this plugin.

What to do

Update, patch or deactivate.

Update Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns to a release after 6.0.4, or disable and remove it until a fixed version is available.

A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.

Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.

Source record

Technical 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.

CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

References

Primary and upstream sources