WordPress Zero Spam Plugin Stored XSS via Contact Form 7

The Zero Spam for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Nested POST Array Keys via Contact Form 7 Integration in all versions up to, and including, 5.7.10 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 payload is delivered by submitting a Contact Form 7 request with a nested POST array key containing arbitrary HTML or JavaScript — PHP parses the field name into a nested array key, which is stored verbatim in the zerospam_log.submission_data column when Zero Spam flags the submission as spam due to the absence of the zerospam_david_walsh_key field.

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 Zero Spam for WordPress plugin contains a stored cross-site scripting (XSS) vulnerability affecting all versions up to 5.7.10. Attackers can inject malicious JavaScript through nested POST array keys in Contact Form 7 submissions, and because the plugin fails to properly sanitize inputs and escape outputs, this payload persists in the application and executes whenever any user accesses the affected page. This vulnerability is particularly dangerous because it requires no authentication, affects a widely-used WordPress plugin ecosystem, and can compromise any site visitor who encounters the injected content—potentially leading to credential theft, session hijacking, or malware distribution at scale.

Casky's 323 matched skills leverage Claude AI with extended reasoning to detect the attack patterns mapped to MITRE ATT&CK techniques TA0001 (Initial Access) and TA0043 (Reconnaissance). Practitioners using Casky would identify suspicious activity signatures including: malformed nested array parameters in Contact Form 7 POST requests (reconnaissance phase), script tag injections bypassing sanitization filters, and persistence indicators showing stored payloads in database entries or rendered DOM elements. The platform's skills would flag insufficient input validation on array key handling, missing output encoding in template rendering, and gaps in Content Security Policy—allowing detection of both the exploitation attempt and the latent vulnerability before widespread compromise occurs.

Live Threat IntelligenceComing soon

Casky Risk Score

—

EPSS Probability

—

Shodan Exposure

—

GreyNoise Signal

—

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-2026-96752.

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-2026-96752

Casky has 323 skills that investigate the attack patterns behind CVE-2026-96752. Run one and get CVSS-scored findings in 3 minutes.

Run the skill that detects this →

X Instagram LinkedIn