# User Registration & Membership – Free & Paid Memberships, Subscriptions, Content Restriction, User Profile, Custom User Registration & Login Builder <= 5.2.8 - Authenticated (Subscriber+) Stored Cross-Site Scripting via Checkbox Field Value

- **ID:** WPSEC-2026-0823
- **Plugin:** User Registration & Membership – Free & Paid Memberships, Subscriptions, Content Restriction, User Profile, Custom User Registration & Login Builder (`user-registration`), https://wordpress.org/plugins/user-registration/
- **Affected versions:** all versions before 5.3.0
- **Fixed in:** 5.3.0 (Update to 5.3.0 or later.)
- **Severity:** Medium 6.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N)
- **Weakness:** CWE-79
- **Usage among sites WPSec scans:** plugin Medium, affected versions Medium (as of 2026-10-13)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/user-registration
- **Fix released:** 2026-10-12
- **Published:** 2026-10-13
- **URL:** https://wpsec.com/vuln/WPSEC-2026-0823/

## Description

The User Registration & Membership plugin for WordPress is vulnerable to Stored Cross-Site Scripting via checkbox form field values in all versions up to, and including, 5.2.8. The user_registration_form_field() function writes the user-controlled stored value into the data-value attribute without escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts. The scripts execute whenever a user, including an administrator, views a page that renders the affected profile field.

## References

- https://wpsec.com/vuln/WPSEC-2026-0823/
- https://plugins.svn.wordpress.org/user-registration/tags/5.3.0/
- https://wordpress.org/plugins/user-registration/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-0823/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.