What the vulnerability does
01Description
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.
Explanation of Vulnerability in Simple Terms
02Summary
A critical vulnerability in CleanTalk's Spam Protection plugin versions 6.71 and earlier allows unauthenticated attackers to read sensitive data, modify site content, or disrupt service without any user interaction. The vulnerability stems from improper input validation or access control. All sites running affected versions require immediate patching.
What an attacker can do
03Attacker Capabilities
Read sensitive data, modify site content, or disrupt service without authentication.
Potential impact on your site
04Site Impact
Attackers can compromise your site's data, content, and availability without needing a user account.
Conditions required to exploit
05Prerequisites
Network access only; no authentication or user interaction required.
Key dates
06Disclosure timeline
February 15, 2026
CVE published
April 8, 2026
Record updated
