Privilege escalation in User Registration & Membership

CVE-2026-86406

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.

Vulnerability class: Privilege Escalation

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (25.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-86406: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

  • User Registration & Membership

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-86406?
CVE-2026-86406 is a high-severity vulnerability in User Registration & Membership, classified under Improper Privilege Management. CVSS score: 7.5/10. Published 2026-09-13.
How severe is CVE-2026-86406?
High severity. CVSS v3 base score is 7.5 out of 10.