CVE-2026-87111
7.2HighPublished 16 Oct 2026 · NVD status: Deferred · AI triage by gemini-3.8-flash
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Impact
- Limited impact
- Weakness
- CWE-79
Impact
Unauthenticated attackers can inject persistent malicious scripts that execute in visitors' and admins' browsers. They only need network access to send a crafted HTTP Referer header to a public AJAX endpoint using nonces leaked in the front-end source.
Root cause
The plugin fails to sanitize and escape the HTTP Referer header before storing it and displaying it on pages.
Affected systems
User Registration PRO (WordPress premium build) up to and including 6.2.9 (free WordPress.org build is not affected).
CVSS v3.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Fix & remediation
Upgrade User Registration PRO to a version newer than 6.2.9 once available from the vendor changelog. If patching immediately is not possible, disable the User Registration PRO plugin or block untrusted characters in HTTP Referer headers via your WAF/reverse proxy.
$ wp plugin list --name=user-registration-proAI-suggested. Run it in staging first and check it against the vendor advisory. Why?
NVD description
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.