CVE-2026-93755
Deferred Deferred - Pending Action

Stored XSS in Happyforms WordPress Plugin via Spoofable Client IP Headers

Publication date: 2026-11-07

Last updated on: 2026-11-07

Assigner: Wordfence

Description
The Happyforms plugin for WordPress is vulnerable to Stored Cross-Site Scripting via spoofable client IP headers in versions up to, and including, 1.38.9. This is due to the happyforms_get_client_ip() function reading raw HTTP_CLIENT_IP and HTTP_X_FORWARDED_FOR request headers without any validation or sanitization, storing the value as post meta ('client_ip') via update_post_meta() during unauthenticated form submissions, and later echoing it in the admin submission edit screen's Details metabox without output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user (typically an administrator reviewing a submission) 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-2026-93755
EUVD
EUVD-2026-119136

Affected Vendors & Products

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

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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

The Happyforms WordPress plugin has a stored Cross-Site Scripting (XSS) vulnerability in versions up to 1.38.9. It occurs because the plugin reads unvalidated client IP headers (HTTP_CLIENT_IP and HTTP_X_FORWARDED_FOR) during form submissions. Attackers can inject malicious scripts that get stored as post meta data. When an admin views the submission details, the unsanitized script executes in their browser.

Detection Guidance

Check for unauthenticated form submissions in Happyforms plugin logs or database entries storing client IP metadata. Look for suspicious IP addresses or scripts in the 'client_ip' post meta field.

Impact Analysis

Unauthenticated attackers can inject malicious scripts into your WordPress site via form submissions. When an administrator reviews the submission, the script runs in their browser, potentially stealing session cookies, redirecting to phishing pages, or performing admin actions on their behalf. This requires no user interaction beyond viewing the submission.

Compliance Impact

This vulnerability could lead to unauthorized access to user data, violating GDPR's data protection requirements and HIPAA's security rules for protected health information. If exploited, it may result in data breaches, triggering mandatory breach notifications and potential fines under these regulations.

Mitigation Strategies

Update the Happyforms plugin to version 1.38.10 or later to address the vulnerability. If immediate update is not possible, disable the plugin or restrict access to admin submission edit screens until patched.

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