CVE-2026-6675
Received Received - Intake
Unauthenticated Open Email Relay in Responsive Blocks Plugin

Publication date: 2026-04-21

Last updated on: 2026-04-21

Assigner: Wordfence

Description
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.
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Meta Information
Published
2026-04-21
Last Modified
2026-04-21
Generated
2026-06-16
AI Q&A
2026-04-21
EPSS Evaluated
2026-06-14
NVD
CVE-2026-6675
EUVD
EUVD-2026-24058
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
responsive_blocks page_builder_for_blocks_and_patterns to 2.2.0 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-20 The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
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Executive Summary

The vulnerability exists in the Responsive Blocks – Page Builder for Blocks & Patterns plugin for WordPress, affecting all versions up to and including 2.2.0.

It is an Unauthenticated Open Email Relay issue caused by insufficient authorization checks and missing server-side validation of the recipient email address supplied via a public REST API route.

This allows unauthenticated attackers to send arbitrary emails to any recipient through the affected WordPress site's mail server, effectively turning the site into an open mail relay.

Impact Analysis

This vulnerability can be exploited by attackers to send arbitrary emails through your WordPress site's mail server without authentication.

As a result, your site could be used to send spam or malicious emails, potentially damaging your domain's reputation and leading to blacklisting by email providers.

It may also increase the risk of your server being involved in phishing or other email-based attacks.

Compliance Impact

The vulnerability allows unauthenticated attackers to use the affected WordPress site as an open mail relay to send arbitrary emails. This could potentially lead to misuse of the site’s mail server for spam or phishing attacks.

However, there is no specific information provided about direct impacts on compliance with common standards and regulations such as GDPR or HIPAA.

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