CVE-2026-93766
Deferred Deferred - Pending Action

Stored XSS in Happyforms Pro WordPress Plugin

Publication date: 2026-11-07

Last updated on: 2026-11-07

Assigner: Wordfence

Description
The Happyforms Pro plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'happyforms_client_referer' parameter in all versions up to, and including, 1.38.9 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.

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Meta Information

Published
2026-11-07
Last Modified
2026-11-07
Generated
2026-11-07
AI Q&A
2026-11-07
EPSS Evaluated
N/A
NVD
CVE-2026-93766
EUVD
EUVD-2026-119151

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
Happyforms Happyforms Pro From 0 (inc) to 1.38.9 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

This is a Stored Cross-Site Scripting (XSS) vulnerability in the Happyforms Pro WordPress plugin. It allows unauthenticated attackers to inject malicious scripts via the 'happyforms_client_referer' parameter due to poor input sanitization and output escaping. The scripts execute when users access an infected page.

Detection Guidance

To detect this vulnerability, inspect WordPress sites using Happyforms Pro versions up to 1.38.9 for stored XSS via the 'happyforms_client_referer' parameter. Check server logs for suspicious referral links or injected scripts in pages.

Impact Analysis

Attackers could steal user sessions, redirect to malicious sites, or perform actions on behalf of users. Website visitors may have their data compromised if they access a page with injected scripts.

Compliance Impact

This vulnerability could lead to unauthorized data access or modification, violating GDPR's data protection requirements and HIPAA's security rules for protected health information.

Mitigation Strategies
  • Update Happyforms Pro to version 1.38.10 or later to patch the vulnerability.
  • Review and remove any suspicious scripts or links in your WordPress site, especially in pages accessed via referral.
  • Monitor for unauthorized changes or unusual activity in your WordPress installation.

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