{"cve":"CVE-2026-4658","nvd":{"published":"2026-05-02T05:16:00.767","modified":"2026-06-17T10:56:59.143","status":"Deferred","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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N","score":6.4},"cwes":["CWE-79"],"references":["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/tags/6.0.4/includes/Blocks/AddToCart.php#L120","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/tags/6.0.4/includes/Blocks/AddToCart.php#L66","https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L118"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:33:09.003606135+00:00"},"epss":{"cve":"CVE-2026-4658","score":0.00419,"percentile":0.362,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}