CVE-2026-4658
Gutenberg Essential Blocks <= 6.0.4 - Authenticated (Contributor+) Stored Cross-Site Scripting via Block Attributes
- 6.4MediumCVSS base score
- 0.42%Exploitation in 30 daysEPSS · top 63% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By Wordfence
- 40 days later
· 40 days later
Published
- 2 days later
· 2 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| WordfenceCNA (assigner) | 3.1 | Medium6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
| NVDNVD · Deferred | 3.1 | Medium6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.42% · top 63% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.4.
Affected products
References
References10
- https://www.wordfence.com/threat-intel/vulnerabilities/id/3e7eed9d-2d44-4951-b66b-7d8995ca617d?source=cve (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L118 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/Blocks/AddToCart.php#L118 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L120 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/Blocks/AddToCart.php#L120 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L65 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/Blocks/AddToCart.php#L65 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/Blocks/AddToCart.php#L66 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/essential-blocks/tags/6.0.4/includes/Blocks/AddToCart.php#L66 (opens in a new tab)
- 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 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-26733 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-4658)Record last updated .