Stored cross-site scripting in Anti-Spam by CleanTalk plugin
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.
Summary
The Anti-Spam by CleanTalk plugin for WordPress is affected in all versions up to and including 6.88. Insufficient input sanitization and output escaping of the comment parameter allow stored cross-site scripting (CWE-79). An unauthenticated attacker can inject scripts that run in the browser of site visitors who access the injected page, once a comment from the attacker's email address is approved, which happens automatically for subsequent comments on default WordPress installations.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
The sources list no fixed version for Anti-Spam by CleanTalk.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Timeline
- 2026-10-10 Threatist record created from CVE-2026-103424
- 2026-10-10 Alias added: GHSA-xx63-6r6g-3hcj
- 2026-10-11 CISA SSVC decision points changed
- 2026-10-11 Priority changed: MEDIUM → LOW
References
Other 6
- https://www.wordfence.com/threat-intel/vulnerabilities/id/c3a80bcd-170b-469b-b090-8f806f87b8d7?source=cve
- https://plugins.trac.wordpress.org/browser/cleantalk-spam-protect/tags/6.88/lib/Cleantalk/Common/ContactsEncoder/ContactsEncoder.php#L831
- https://plugins.trac.wordpress.org/browser/cleantalk-spam-protect/tags/6.88/lib/Cleantalk/Common/ContactsEncoder/ContactsEncoder.php#L841
- https://plugins.trac.wordpress.org/browser/cleantalk-spam-protect/tags/6.88/lib/Cleantalk/Common/ContactsEncoder/ContactsEncoder.php#L273
- https://plugins.trac.wordpress.org/browser/cleantalk-spam-protect/tags/6.88/lib/Cleantalk/ApbctWP/ContactsEncoder/ContactsEncoder.php#L97
- https://plugins.trac.wordpress.org/browser/cleantalk-spam-protect/tags/6.88/cleantalk.php#L248
More cleantalk vulnerabilities
- TI-2022-03051 Anti-Spam by CleanTalk < 5.185.1 - Admin+ SQLi CVSS 3.1HIGH 7.2
- TI-2024-09765 Missing authorization in cleantalk Spam protection, Honeypot, Anti-Spam by CleanTalk CVSS 3.1CRITICAL 9.8
- TI-2024-12407 Security & Malware scan by CleanTalk <= 2.149 - Unauthenticated Arbitrary File Upload CVSS 3.1CRITICAL 9.8
- TI-2026-01186 Spam protection, Honeypot, Anti-Spam by CleanTalk <= 6.71 - Authorization Bypass via… CVSS 3.1CRITICAL 9.8
- TI-2026-47264 WordPress Security & Malware scan by CleanTalk plugin <= 2.184 - SQL Injection vulnerability CVSS 3.1CRITICAL 9.3
- TI-2024-09993 Spam protection, Anti-Spam, FireWall by CleanTalk <= 6.44 - Authorization Bypass due to… CVSS 3.1HIGH 8.1
Sources
- CVE-2026-103424 · CVE Program
- CVE-2026-103424 · NVD
- FIRST EPSS
- GHSA-xx63-6r6g-3hcj · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences