CVE-2026-6675Network attack vector

Unauthenticated email relay via unchecked REST recipient

Published Apr 21, 2026 · Updated Apr 21, 2026

Open email relay in CyberChimps Responsive Blocks 2.2.0 and earlier allows remote attackers to send email to arbitrary recipients. The Form Block's public REST route accepts an attacker-controlled email_to recipient and passes it to the site's mail function without authorization or server-side recipient validation. No WordPress account or user interaction is required, and successful requests send attacker-chosen messages through the site's configured mail server.

CVSS severity5.3
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open email relay in CyberChimps Responsive Blocks 2.2.0 and earlier allows remote attackers to send email to arbitrary recipients. The Form Block's public REST route accepts an attacker-controlled email_to recipient and passes it to the site's mail function without authorization or server-side recipient validation. No WordPress account or user interaction is required, and successful requests send attacker-chosen messages through the site's configured mail server.

The record

CVE
CVE-2026-6675
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
CyberChimps
Product
Responsive Blocks
Classifications
CWE-20
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

CyberChimps · Responsive Blocksversion=0 <=2.2.0

Published CVSS scores

5.3WordfenceCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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