CVE-2026-4658 - Essential Blocks Plugin
CVE-2026-4658
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-2026-4658
MEDIUM
CVSS 6.4
Published 2026-05-02
Updated 2026-05-05
AI Risk Elevated (63/100)
Active Exploit: No strong signal
Published Exploit: No public exploit references
Priority: P3 Priority
Severity Band
MEDIUM
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Affected Components
2
Reference Links
10
AI Risk Engine
Elevated (63/100)
Exploitability
High
Active Exploitation
No strong signal
Published Exploit Status
No public exploit references
AI Context
Machine-generated threat intelligence
AI
Updated 8 days ago
AI enriched 8 days ago (2026-05-23 20:18 UTC)
Technical 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…
Potential Impact
Severity is MEDIUM (CVSS 6.4). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.
Exploitability Assessment
Exploitability is assessed as High based on remote code execution potential.
Primary risk drivers: remote code execution potential
Mitigation Recommendations
Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.
Detection & Monitoring
Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.
Business Impact Lens
AI risk score 63/100 (Elevated, High) with priority P3 Priority. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.
