CVE-2026-4658
Stored XSS in Essential Blocks WordPress Plugin
Publication date: 2026-05-02
Last updated on: 2026-05-05
Assigner: Wordfence
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| essential_blocks | page_builder_gutenberg_blocks_patterns_templates | to 6.0.4 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-79 | The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. |
Attack-Flow Graph
AI Powered Q&A
How can this vulnerability impact me? :
This vulnerability allows attackers with Contributor-level access or above to inject malicious scripts into pages via the Add to Cart block.
When other users visit these pages, the injected scripts execute in their browsers, potentially leading to theft of sensitive information, session hijacking, or other malicious actions.
The impact includes loss of data integrity and confidentiality, and it may compromise user trust and site security.
Can you explain this vulnerability to me?
The vulnerability exists in the Essential Blocks – Page Builder Gutenberg Blocks, Patterns & Templates plugin for WordPress, specifically in the Add to Cart block (essential-blocks/add-to-cart) in all versions up to and including 6.0.4.
It is a Stored Cross-Site Scripting (XSS) vulnerability caused by insufficient output escaping in the render_callback() function. The className, classHook, and blockId attributes are inserted into class and data-id HTML attributes using raw sprintf() and implode() functions without proper escaping (esc_attr()).
While the outer wrapper div is properly escaped, the inner divs are not, allowing authenticated attackers with Contributor-level access or higher to inject arbitrary web scripts. These scripts execute whenever a user accesses the injected page.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability allows authenticated attackers with Contributor-level access and above to inject arbitrary web scripts via Stored Cross-Site Scripting (XSS) in pages. This can lead to unauthorized access or manipulation of user data when users access the injected pages.
Such unauthorized script execution can potentially compromise the confidentiality and integrity of user data, which may impact compliance with data protection regulations like GDPR and HIPAA that require safeguarding personal and sensitive information against unauthorized access or disclosure.
However, the provided information does not explicitly detail the direct compliance impact or specific regulatory implications of this vulnerability.