Gutenberg Essential Blocks <= 6.0.4 - Authenticated (Contributor+) Stored Cross-Site Scripting via Block Attributes
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| wpdevteam | Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns | up to 6.0.4 | — | No fix listed | CNA |
- Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns Vendorwpdevteam Affected up to 6.0.4 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-4658
- 2026-10-03 Alias added: GHSA-5vvh-659m-gjm3
References
Other 10
- https://www.wordfence.com/threat-intel/vulnerabilities/id/3e7eed9d-2d44-4951-b66b-7d8995ca617d?source=cve
- https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L118
- 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/trunk/includes/Blocks/AddToCart.php#L120
- 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/trunk/includes/Blocks/AddToCart.php#L65
- 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/trunk/includes/Blocks/AddToCart.php#L66
- https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/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
More wpdevteam vulnerabilities
- TI-2024-01579 SQL injection in wpdevteam NotificationX – FOMO, Live Sales Notification, WooCommerce… CVSS 3.1CRITICAL 9.8
- TI-2023-15541 WordPress Essential Addons for Elementor Plugin 5.4.0-5.7.1 is vulnerable to Privilege Escalation CVSS 3.1CRITICAL 9.8
- TI-2023-06070 Essential Blocks < 4.4.3 - Unauthenticated Local File Inclusion CVSS 3.1CRITICAL 9.8
- TI-2023-11478 SQL injection in ReviewX WordPress Plugin CVSS 3.1HIGH 8.8
- TI-2022-00275 NotificationX < 2.3.9 - Unauthenticated Blind SQL Injection CVSS 3.1CRITICAL 9.8
- TI-2024-05197 Essential Blocks < 4.7.0 - Contributor+ Stored XSS CVSS 3.1MEDIUM 5.4
Sources
- CVE-2026-4658 · CVE Program
- CVE-2026-4658 · NVD
- FIRST EPSS
- GHSA-5vvh-659m-gjm3 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences