WordPress Contact Form 7 Plugin Stored XSS via Author Parameter

The Magic Tooltips For Contact Form 7 plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'author' parameter in all versions up to, and including, 1.0.34 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 is possible because the plugin's esc_html filter callback decodes HTML-entity-encoded payloads (e.g. those containing '<tip>') back into live HTML, meaning an entity-encoded script payload submitted as a comment author name — which bypasses sanitize_text_field — is rendered as executable markup when an administrator views wp-admin/edit-comments.php.

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

The Magic Tooltips For Contact Form 7 plugin contains a stored cross-site scripting (XSS) vulnerability in versions up to 1.0.34 that allows unauthenticated attackers to inject malicious scripts through the 'author' parameter. The vulnerability stems from insufficient input sanitization combined with improper output escaping—specifically, the plugin's esc_html filter callback actually decodes HTML entities, inadvertently converting encoded payloads back into executable script. This stored XSS is particularly dangerous because injected scripts persist in the database and execute for all users who view the affected pages, making it a widespread attack vector. WordPress site administrators and any organizations relying on Contact Form 7 for lead generation or customer communication are at risk, as are their site visitors who may be compromised through credential theft, malware distribution, or session hijacking.

Casky's 323 mapped skills detect this vulnerability by analyzing attack patterns aligned with MITRE techniques TA0001 (Initial Access) and TA0043 (Reconnaissance). Claude AI's extended reasoning identifies suspicious author parameter inputs that bypass sanitization filters and recognizes the entity-decoding anti-pattern that reactivates encoded payloads. Practitioners using Casky would observe findings highlighting: (1) CWE-79 violations where user input flows directly to output without proper HTML context escaping, (2) detection of script injection attempts in form parameters that survive the plugin's inadequate filtering, and (3) stored payload persistence indicators showing malicious content lodged in database records. The platform flags the gap between input sanitization and output encoding as a critical control failure, enabling security teams to prioritize remediation and audit existing Contact Form 7 instances for exploitation evidence.

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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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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-2026-101928.

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-2026-101928

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