CVE-2026-86407: User Registration & Membership < 5.2.8 - Unauthenticated User Data Disclosure via Membership Thank You Page
The User Registration & Membership WordPress plugin before 5.2.8 does not verify that the visitor requesting its membership confirmation page owns the account named in the request, nor that any registration or purchase has taken place, allowing unauthenticated users to retrieve another user's email address, profile fields, role and membership order details. Exploitation requires the site owner to have added a user smart tag to that page's configurable message, which the shipped default does not contain.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
wordpress/User Registration & Membershipto a version that resolves this vulnerability.Fixed in 5.2.8 - Compensating control
Ensure the Membership Thank You page does not have a user smart tag added to its configurable message; the shipped default does not contain this smart tag and exploitation requires the site owner to add it.
Event History
Frequently Asked Questions
Which sites are exposed in practice?
Sites using User Registration & Membership versions before 5.2.8 are exposed only if the configurable membership confirmation/thank-you page message includes a user smart tag. The shipped default message does not include such a tag.
What does an attacker need to exploit this issue?
An attacker does not need to authenticate, register, or complete a purchase. They need to request the membership confirmation page with another account named in the request, on a site whose page message contains a user smart tag.
What information could be disclosed?
The issue can expose another user's email address, profile fields, role, and membership order details. The exact data returned depends on the user smart tag configured in the page message.
What can be done if updating is not immediately possible?
Remove user smart tags from the configurable membership confirmation/thank-you page message. This removes the configuration condition required for exploitation.