---
id: CVE-2026-103424
title: >-
  The Anti-Spam by CleanTalk – Spam Protection Without CAPTCHA plugin for
  WordPress is vulnerable to Stored Cross-Site Scripting via the 'comment'
  parameter in all versions up to, and including, 6.88 due to insufficient input
  sanitization …
summary: >-
  The Anti-Spam by CleanTalk – Spam Protection Without CAPTCHA plugin for
  WordPress is vulnerable to Stored Cross-Site Scripting via the 'comment'
  parameter in all versions up to, and including, 6.88 due to insufficient input
  sanitization …
severity: medium
cvss: 5.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N'
cwe:
  - CWE-79
published: '2026-10-10'
updated: '2026-10-10'
sourceUpdated: '2026-10-10T05:16:39.003'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-103424'
references:
  - url: >-
      https://plugins.trac.wordpress.org/browser/cleantalk-spam-protect/tags/6.88/cleantalk.php#L248
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/cleantalk-spam-protect/tags/6.88/lib/Cleantalk/ApbctWP/ContactsEncoder/ContactsEncoder.php#L97
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/cleantalk-spam-protect/tags/6.88/lib/Cleantalk/Common/ContactsEncoder/ContactsEncoder.php#L273
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/cleantalk-spam-protect/tags/6.88/lib/Cleantalk/Common/ContactsEncoder/ContactsEncoder.php#L831
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/cleantalk-spam-protect/tags/6.88/lib/Cleantalk/Common/ContactsEncoder/ContactsEncoder.php#L841
    label: security@wordfence.com
  - url: >-
      https://www.wordfence.com/threat-intel/vulnerabilities/id/c3a80bcd-170b-469b-b090-8f806f87b8d7?source=cve
    label: security@wordfence.com
tags:
  - nvd
ingestedAt: '2026-10-10T05:23:33.489Z'
---

## Overview

The Anti-Spam by CleanTalk – Spam Protection Without CAPTCHA plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'comment' parameter in all versions up to, and including, 6.88 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. This vulnerability is exploitable once a comment from the attacker's email address has been approved; on default WordPress installations, only the first comment from a given email address is held for moderation, meaning subsequent comments auto-approve and immediately expose the payload to site visitors.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.