Responsive Blocks <= 2.2.0 - Unauthenticated Open Email Relay via REST API 'email_to' Parameter

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-6675
StatePUBLISHED
AssignerWordfence
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-21 03:16:09 UTC
Updated2026-04-21 03:16:09 UTC
DescriptionThe Responsive Blocks – Page Builder for Blocks & Patterns plugin for WordPress is vulnerable to Unauthenticated Open Email Relay in all versions up to, and including, 2.2.0. This is due to insufficient authorization checks and missing server-side validation of the recipient email address supplied via a public REST API route. This makes it possible for unauthenticated attackers to send arbitrary emails to any recipient of their choosing through the affected WordPress site's mail server, effectively turning the site into an open mail relay.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Problem Types: CWE-20 | CWE-20 CWE-20 Improper Input Validation

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
3.1CNADECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Cyberchimps Responsive Blocks Page Builder For Blocks Patterns affected 2.2.0 semver Not specified

References

ReferenceSourceLinkTags
plugins.trac.wordpress.org/browser/responsive-block-editor-addons/trunk/includes/class-r... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/responsive-block-editor-addons/trunk/includes/class-r... [email protected] plugins.trac.wordpress.org
www.wordfence.com/threat-intel/vulnerabilities/id/17452a29-bcef-451a-9893-a436a... [email protected] www.wordfence.com
plugins.trac.wordpress.org/browser/responsive-block-editor-addons/trunk/includes/class-r... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/responsive-block-editor-addons/tags/2.1.9/includes/cl... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/responsive-block-editor-addons/tags/2.1.9/includes/cl... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/responsive-block-editor-addons/tags/2.1.9/includes/cl... [email protected] plugins.trac.wordpress.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Even Stokkedalen (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-04-20T14:13:38.000ZDisclosed
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