Happyforms Pro <= 1.38.9 - Unauthenticated Stored Cross-Site Scripting via Client-IP/X-Forwarded-For Header
Strategic Overview
- Status
- Patched in 1.38.10
- Affected Plugin
- Happyforms Pro
- Affected Version
<= 1.38.9- CVSS
- 7.2High
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation
- CVE
CVE-2026-93755
At a glance
CVE-2026-93755 is a high-severity Improper Neutralization of Input During Web Page Generation vulnerability in the Happyforms Pro WordPress plugin, affecting versions <= 1.38.9. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.38.10; sites on affected versions should update now. Disclosed November 2026, reported by Bao Le.
Vulnerability Overview
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.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.
CWE-79: Improper Neutralization of Input During Web Page Generation
Happyforms Pro <= 1.38.9 carries this weakness at client_ip, and reaching it takes no account at all. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.
Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Happyforms Pro the fix is 1.38.10: builds <= 1.38.9 are affected, anything from 1.38.10 onward is not.
Remediation
Update to version 1.38.10, or a newer patched version
How does WordSec protect against this?
Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Happyforms Pro 1.38.10 closes this, and updating the plugin is the step that ends it.
- Firewall
- Login Security
- Alerts
External References
Related records
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