CVE-2026-86406: Unknown User Registration & Membership

High severity, CVSS 7.5. EPSS: 0.3% chance of exploitation in the next 30 days.

The User Registration & Membership WordPress plugin before 5.2.8 does not check the capability of the user making a membership purchase, and does not validate the payment method or the plan submitted with it, allowing any authenticated user such as a subscriber to be granted the WordPress role attached to a paid plan without paying for it. Where the site owner has mapped a plan to a privileged role, this leads to privilege escalation up to administrator.

Affected products

• Unknown User Registration & Membership: from 4.4.6, before 5.2.8 (fixed in 5.2.8)

Published 2026-09-13. Last modified 2026-09-14.