CVE-2026-1869

User Registration & Membership <= 5.2.0 - Missing Authorization to Unauthenticated Payment Bypass

2026-06-25 19:44
Supakiad S. (m3ez)

At a glance

CVE-2026-1869 is a medium-severity Missing Authorization vulnerability in the User Registration & Membership WordPress plugin, affecting versions <= 5.2.0. It carries a CVSS score of 6.5 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 5.2.1; sites on affected versions should update now. Disclosed June 2026, reported by Supakiad S. (m3ez).

Vulnerability Overview

The User Registration & Membership – Free & Paid Memberships, Subscriptions, Content Restriction, User Profile, Custom User Registration & Login Builder plugin for WordPress is vulnerable to unauthorized modification of data due to missing validation checks in the confirm_payment() function in all versions up to, and including, 5.2.0. This makes it possible for unauthenticated attackers to bypass payment processing and activate paid memberships.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-862: Missing Authorization

User Registration & Membership <= 5.2.0 carries this weakness at confirm_payment(), and reaching it takes no account at all. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.

Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For User Registration & Membership the fix is 5.2.1: builds <= 5.2.0 are affected, anything from 5.2.1 onward is not.

Remediation

Update to version 5.2.1, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: User Registration & Membership 5.2.1 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

Related records

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