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Spam protection, Honeypot, Anti-Spam by CleanTalk <= 6.71 — Authorization Bypass via Reverse DNS (PTR record) Spoofing to Unauthenticated Arbitrary Plugin Installation

CVE-2026-1490Published · Updated

Action summary

Affected: ≤6.71Update to 6.72 or newer

All remediation steps
Watch plugin
Severity
Critical9.8
CVSS
9.8
CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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:H Confidentiality
High
I:H Integrity
High
A:H Availability
High
Weakness
CWE-350 Reliance on Reverse DNS Resolution for a Security-Critical Action
Required access
No account needed
Exploit prediction (EPSS)
No score
CISA KEV
Not listed
On this page8

Am I affected?

Anti-Spam, Spam FireWall by CleanTalk cleantalk-spam-protect

  1. Affected≤ 6.71
  2. Patched in6.72

Update to 6.72 or newer.

You are affected if you run ≤ 6.71. Version 6.72 and later are not affected by this issue.

  • Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Anti-Spam, Spam FireWall by CleanTalk.
  • 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 6.72, or a newer patched version
  2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
  3. Watch Anti-Spam, Spam FireWall by CleanTalk to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Nguyen Ngoc Duc (duc193).

The Spam protection, Anti-Spam, FireWall by CleanTalk plugin for WordPress is vulnerable to unauthorized Arbitrary Plugin Installation due to an authorization bypass via reverse DNS (PTR record) spoofing on the 'checkWithoutToken' function in all versions up to, and including, 6.71. This makes it possible for unauthenticated attackers to install and activate arbitrary plugins which can be leveraged to achieve remote code execution if another vulnerable plugin is installed and activated. Note: This is only exploitable on sites with an invalid API key.

Exploits & references

Proof-of-concept & detection

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

Advisories & patches

More in Anti-Spam, Spam FireWall by CleanTalk

All 20
More vulnerabilities in Anti-Spam, Spam FireWall by CleanTalk
SeverityVulnerabilityCVEPublished
High7.2Unauthenticated Stored Cross-Site Scripting
≤6.90Update to 6.91
CVE-2026-115673
High7.2Unauthenticated Stored Cross-Site Scripting via 'user_email' Registration Parameter
≤6.89.1Update to 6.90
CVE-2026-109198
Medium5.4Unauthenticated Stored Cross-Site Scripting via Comment Content via ContactsEncoder Greedy Regex
≤6.88Update to 6.89
CVE-2026-103424
Medium6.5Unauthenticated Arbitrary Shortcode Execution
<6.87Update to 6.87
CVE-2026-19855
High7.2Unauthenticated Stored Cross-Site Scripting via Comment Content aria-label Placeholder
≤6.86Update to 6.87
CVE-2026-77830

Timeline

  1. CVE published

    Severity critical, CVSS 9.8

  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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