Gutenberg Essential Blocks <= 6.0.4 — Authenticated (Contributor+) Stored Cross-Site Scripting via Block Attributes
CVE-2026-4658Published · Updated Action summary
Affected: ≤6.0.4Update to 6.1.0 or newer
All remediation steps- Severity
- Medium6.4
- CVSS
- 6.4CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:NWhat does this vector mean?
AV:NAttack vector- Network
AC:LAttack complexity- Low
PR:LPrivileges required- Low
UI:NUser interaction- None
S:CScope- Changed
C:LConfidentiality- Low
I:LIntegrity- Low
A:NAvailability- None
- Weakness
- CWE-79 Cross-Site Scripting
- Required access
- Unknown
- Exploit prediction (EPSS)
- No score
- CISA KEV
- Not listed
On this page8
Am I affected?
Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns essential-blocks
- Affected≤ 6.0.4
- Patched in6.1.0
Update to 6.1.0 or newer.
You are affected if you run ≤ 6.0.4. Version 6.1.0 and later are not affected by this issue.
- Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns.
- No admin access? Run a passive check of your site. It reads public files only.
What to do
- Update to version 6.1.0, or a newer patched version
- Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
- Watch Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns to get an email when the next vulnerability is published.
Advisory
Source description from Wordfence Intelligence, credited to AlexHenry, normaandersonfrank.
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.
Exploits & references
Proof-of-concept & detection
No public proof-of-concept or detection template is known for this vulnerability.
Advisories & patches
- Advisorywordfence.com
Related CVEs
More in Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns
All 34| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| Medium6.4 | Authenticated (Contributor+) Stored Cross-Site Scripting via 'marker' Attribute ≤6.4.5Update to 6.4.6 | CVE-2026-96256 | |
| Medium5.3 | Unauthenticated Information Exposure ≤6.3.0Update to 6.4.0 | CVE-2026-13154 | |
| Medium5.3 | Unauthenticated Information Exposure ≤6.3.0Update to 6.4.0 | CVE-2026-13153 | |
| Medium6.4 | Page Builder for Gutenberg Blocks & Patterns <= 6.1.4 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'configurablePrefix' Block Attribute ≤6.1.4Update to 6.2.0 | CVE-2026-10833 | |
| High7.2 | Authenticated (Author+) Server-Side Request Forgery ≤6.1.3Update to 6.1.4 | CVE-2026-10586 |
- Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting via 'marker' Attribute
≤6.4.5Update to 6.4.6
- Medium5.3Unauthenticated Information Exposure
≤6.3.0Update to 6.4.0
- Medium5.3Unauthenticated Information Exposure
≤6.3.0Update to 6.4.0
- Medium6.4Page Builder for Gutenberg Blocks & Patterns <= 6.1.4 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'configurablePrefix' Block Attribute
≤6.1.4Update to 6.2.0
- High7.2Authenticated (Author+) Server-Side Request Forgery
≤6.1.3Update to 6.1.4
Same weakness (Cross-Site Scripting)
All Cross-Site Scripting| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| High7.2 | Unauthenticated Stored Cross-Site Scripting via Comment User-Agent Header | CVE-2026-120688 | |
| Critical9.8 | Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission | CVE-2026-125055 | |
| Critical9.8 | Unauthenticated PHP Object Injection to Remote Code Execution via 'form' Parameter | CVE-2026-119077 | |
| Medium5.3 | Unauthenticated Sensitive Information Exposure in 'search' Parameter | CVE-2026-121518 |
- High7.2Unauthenticated Stored Cross-Site Scripting via Comment User-Agent Header
EZ SQL Reports Shortcode Widget and DB Backup
≤5.25.25Update to 5.26.45
- Critical9.8Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission
Chatterbug Forms – Fast, Flexible WordPress Form Builder
≤1.0.2Update to 1.1
- Critical9.8Unauthenticated PHP Object Injection to Remote Code Execution via 'form' Parameter
ELEX WordPress HelpDesk & Customer Ticketing System
≤3.3.9Update to 3.4.0
- Medium5.3Unauthenticated Sensitive Information Exposure in 'search' Parameter
Customer Reviews for WooCommerce
≤5.127.0Update to 5.128.0
Timeline
CVE published
Severity medium, CVSS 6.4
Record last updated
Sources & licenses
Wordfence record- Vulnerability data
- Wordfence Intelligence. [object Object] Licensed under the CC BY-SA 4.0.
- CVE® identifiers
- [object Object]. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
- CVSS / CWE
- National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
- VulnCrest content
- Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.