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

CVE-2026-6675Published · Updated

Action summary

Affected: ≤2.2.0Update to 2.2.1 or newer

All remediation steps
Watch plugin
Severity
Medium5.3
CVSS
5.3
CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
What does this vector mean?
AV:N Attack vector
Network
AC:L Attack complexity
Low
PR:N Privileges required
None
UI:N User interaction
None
S:U Scope
Unchanged
C:N Confidentiality
None
I:L Integrity
Low
A:N Availability
None
Weakness
CWE-20 Improper Input Validation
Required access
No account needed
Exploit prediction (EPSS)
No score
CISA KEV
Not listed
On this page8

Am I affected?

Responsive Blocks – Page Builder for Blocks & Patterns responsive-block-editor-addons

  1. Affected≤ 2.2.0
  2. Patched in2.2.1

Update to 2.2.1 or newer.

You are affected if you run ≤ 2.2.0. Version 2.2.1 and later are not affected by this issue.

  • Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Responsive Blocks – Page Builder for Blocks & Patterns.
  • No admin access? Run a passive check of your site. It reads public files only.
  • No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

  1. Update to version 2.2.1, or a newer patched version
  2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
  3. Watch Responsive Blocks – Page Builder for Blocks & Patterns to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Even Stokkedalen.

The 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.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

More in Responsive Blocks – Page Builder for Blocks & Patterns

All 11
More vulnerabilities in Responsive Blocks – Page Builder for Blocks & Patterns
SeverityVulnerabilityCVEPublished
Medium4.7Unauthenticated Arbitrary HTML Injection in Notification Email
<2.3.0Update to 2.3.0
CVE-2026-97315
Medium4.3Missing Authorization to Authenticated (Contributor+) Arbitrary Modification via AJAX Actions
2.0.9 – 2.2.1Update to 2.2.2
CVE-2026-6703
Medium5.3Missing Authorization
≤2.2.0Update to 2.2.1
CVE-2026-32543
Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting
≤2.0.6Update to 2.0.7
CVE-2025-53202
Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting
≤2.0.5Update to 2.0.6
CVE-2025-49881

Timeline

  1. CVE published

    Severity medium, CVSS 5.3

  2. Record last updated

Sources & licenses

Wordfence record
Vulnerability data
Wordfence Intelligence. Copyright 2012-2026 Defiant Inc. Licensed under the CC BY-SA 4.0.
CVE® identifiers
Copyright 1999-2026 The MITRE Corporation. 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.

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