WordPress CleanTalk Plugin Stored XSS in Comment Aria-Labels

The Spam protection, Honeypot, Anti-Spam by CleanTalk plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content aria-label Placeholder in all versions up to, and including, 6.86 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with custom-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The payload is deliverable via unauthenticated comment submission and executes exclusively for non-logged-in visitors; if comment moderation is enabled, an approving moderator must first publish the comment before the script reaches other users.

Casky was already ahead

This CVE exploits attack patterns that Casky's 323matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

CVE-2026-77830 is a Stored Cross-Site Scripting (XSS) vulnerability in the CleanTalk spam protection plugin for WordPress affecting all versions up to 6.86. The vulnerability exists in how the plugin handles the aria-label placeholder attribute within comment content, failing to properly sanitize and escape user input. This allows authenticated attackers with custom-level access or higher to inject malicious JavaScript that persists in the database and executes whenever any user views the affected page. WordPress sites using this popular security plugin are at risk, particularly installations where contributor-level or higher account compromises occur, turning a defensive tool into an attack vector.

Casky's 323 mapped skills leverage Claude's extended reasoning to detect the attack patterns underlying this vulnerability by analyzing MITRE ATT&CK techniques TA0001 (Initial Access) and TA0043 (Reconnaissance). Practitioners using Casky would identify suspicious comment content containing script tags or event handlers in aria-label attributes, recognize CWE-79 patterns through payload analysis, and spot the gap between input validation and output encoding in plugin code. The platform's skill set enables detection of the injection point, tracing how unsanitized comment data flows through the plugin's rendering logic, and flagging the absence of wp_kses_post() or equivalent escaping functions. Security teams would receive findings highlighting the difference between authentication-based access control and proper input sanitization, revealing how an authenticated user with seemingly limited privileges can compromise page integrity across the entire site.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

323 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-77830.

Abuse of Public-Facing API: Mobile API Abuse

mobile security · low

Run

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

MITRE ATT&CK Techniques

TA0001 TA0043

Investigate the attack patterns behind CVE-2026-77830

Casky has 323 skills that investigate the attack patterns behind CVE-2026-77830. Run one and get CVSS-scored findings in 3 minutes.

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