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

Reliance on Reverse DNS Resolution for a Security-Critical Action
CVE CVE-2026-1490
CVSS Critical (9.8)
Publicly Published February 14, 2026
Last Updated February 15, 2026
Researcher Nguyen Ngoc Duc (duc193)
Description

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.

References

1 affected software package

Software Type Plugin
Software Slug cleantalk-spam-protect (view on wordpress.org)
Patched? Yes
Affected Version
  • <= 6.71
Patched Version
  • 6.72
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