User Registration PRO <= 6.2.9 - Unauthenticated Stored Cross-Site Scripting via HTTP Referer Header
Strategic Overview
- Status
- Patched in 6.3.0
- Affected Plugin
- User Registration PRO – Custom Registration Form, Login Form, and User Profile WordPress Plugin
- Affected Version
<= 6.2.9- CVSS
- 7.2High
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2026-87111
At a glance
CVE-2026-87111 is a high-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the User Registration PRO WordPress plugin, affecting versions <= 6.2.9. 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 6.3.0; sites on affected versions should update now. Disclosed October 2026, reported by andrea bocchetti.
Vulnerability Overview
The User Registration PRO – Custom Registration Form, Login Form, and User Profile WordPress Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via HTTP Referer Header in all versions up to, and including, 6.2.9 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. This vulnerability is present only in the premium build of the plugin and is not present in the free WordPress.org distribution. The nonce required to call the vulnerable AJAX endpoint is localized into the page source of every front-end page for anonymous visitors, making it fully obtainable by unauthenticated attackers.
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 ('Cross-site Scripting')
Reaching this weakness in User Registration PRO <= 6.2.9 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 User Registration PRO the fix is 6.3.0: builds <= 6.2.9 are affected, anything from 6.3.0 onward is not.
Remediation
Update to version 6.3.0, 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: User Registration PRO 6.3.0 closes this, and updating the plugin is the step that ends it.
- Firewall
- Login Security
- Alerts
External References
Related records
Other vulnerabilities in User Registration PRO – Custom Registration Form, Login Form, and User Profile WordPress Plugin
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