The Anti-Spam by CleanTalk – Spam Protection Without CAPTCHA plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'user_email' parameter in all versions up to, and including, 6.89.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Successful exploitation requires user registration to be open on the site, and script execution is triggered when an Administrator subsequently runs the plugin's user-spam scan and views the resulting Non-checkable users or Spam users tab — the plugin's own documented workflow.
The Anti-Spam by CleanTalk – Spam Protection Without CAPTCHA WordPress plugin is vulnerable to stored cross-site scripting (XSS) via the 'comment' parameter in all versions up to and including 6.88. This vulnerability allows unauthenticated attackers to inject malicious scripts that execute when users view the affected pages. Exploitation requires that a comment from the attacker's email address be approved; on default WordPress setups, only the first comment from an email is moderated, so subsequent comments auto-approve and expose the payload immediately.
The CleanTalk Spam protection, Honeypot, Anti-Spam WordPress plugin is affected by a stored cross-site scripting (XSS) vulnerability in versions up to and including 6.86. This vulnerability allows authenticated users with custom-level access or higher to inject malicious scripts via comment content that execute when non-logged-in users view the affected pages. The exploit requires comment approval if moderation is enabled before the script is delivered to other users.
CVE-2026-66593 is a critical unauthenticated SQL Injection vulnerability in the Security & Malware scan by CleanTalk affecting versions up to 2.184. This flaw allows an attacker to inject SQL commands without authentication, potentially leading to high confidentiality impact and limited availability impact. The vulnerability has a CVSS score of 9.3, indicating a severe risk. No patch or remediation information is currently provided by the vendor.
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.
The Login Security, FireWall, Malware removal by CleanTalk plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the page URL in all versions up to, and including, 2.168 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
The Security & Malware scan by CleanTalk plugin for WordPress is vulnerable to arbitrary file uploads due to the plugin uploading and extracting .zip archives when scanning them for malware through the checkUploadedArchive() function in all versions up to, and including, 2.149. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
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 spoofing on the checkWithoutToken function in all versions up to, and including, 6.43.2. 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.
The Spam protection, Anti-Spam, FireWall by CleanTalk plugin for WordPress is vulnerable to unauthorized Arbitrary Plugin Installation due to an missing empty value check on the 'api_key' value in the 'perform' function in all versions up to, and including, 6.44. 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.
The Security & Malware scan by CleanTalk plugin for WordPress is vulnerable to unauthorized SQL Injection due to an authorization bypass via reverse DNS spoofing on the checkWithoutToken function in all versions up to, and including, 2.145, as well as insufficient input sanitization and validation. This makes it possible for unauthenticated attackers to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database.