CVE-2026-6675 | Responsive Blocks <= 2.2.0 - Unauthenticated Open Email Relay via REST API 'email_to' Parameter

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.

Published: 2026-04-21 Last update: 2026-04-22 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-6675 is rated Low Risk (23.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.02%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-6675

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-22 0.06% 0.02% -0.03%
2 2026-04-27 0.05% 0.06% +0.01%
3 2026-04-21 — 0.05% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-6675

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]

Weakness enumeration for CVE-2026-6675

GitHub Security Advisory for CVE-2026-6675

GHSA-jqqm-hx2h-83c5 · Severity: medium — The Responsive Blocks – Page Builder for Blocks & Patterns plugin for WordPress is vulnerable to...

Affected software / configurations for CVE-2026-6675

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-6675

URL Tags
https://plugins.trac.wordpress.org/browser/responsive-block-editor-addons/tags/2.1.9/includes/class-responsive-block-editor-addons.php#L2212
https://plugins.trac.wordpress.org/browser/responsive-block-editor-addons/tags/2.1.9/includes/class-responsive-block-editor-addons.php#L2324
https://plugins.trac.wordpress.org/browser/responsive-block-editor-addons/tags/2.1.9/includes/class-responsive-block-editor-addons.php#L2403
https://plugins.trac.wordpress.org/browser/responsive-block-editor-addons/trunk/includes/class-responsive-block-editor-addons.php#L2212
https://plugins.trac.wordpress.org/browser/responsive-block-editor-addons/trunk/includes/class-responsive-block-editor-addons.php#L2324
https://plugins.trac.wordpress.org/browser/responsive-block-editor-addons/trunk/includes/class-responsive-block-editor-addons.php#L2403
https://www.wordfence.com/threat-intel/vulnerabilities/id/17452a29-bcef-451a-9893-a436ac5d3b80?source=cve
cvelogic Threat Intelligence