CVE-2026-1321

Membership Plugin – Restrict Content <= 3.2.20 - Unauthenticated Privilege Escalation via 'rcp_level'

2026-03-04 00:00
shark3y

Strategic Overview

Status
Patched in 3.2.21
Affected Version
<= 3.2.20
CVSS
8.1High
Weakness type
CWE-862 · Missing Authorization
CVE
CVE-2026-1321
View all Membership Plugin – Kadence Memberships vulnerabilities

At a glance

CVE-2026-1321 is a high-severity Missing Authorization vulnerability in the Membership Plugin WordPress plugin, affecting versions <= 3.2.20. It carries a CVSS score of 8.1 (reachable over the network; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 3.2.21; sites on affected versions should update now. Disclosed March 2026, reported by shark3y.

Vulnerability Overview

The Membership Plugin – Restrict Content plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 3.2.20. This is due to the `rcp_setup_registration_init()` function accepting any membership level ID via the `rcp_level` POST parameter without validating that the level is active or that payment is required. Combined with the `add_user_role()` method which assigns the WordPress role configured on the membership level without status checks, this makes it possible for unauthenticated attackers to register with any membership level, including inactive levels that grant privileged WordPress roles such as Administrator, or paid levels that charge a sign-up fee. The vulnerability was partially patched in version 3.2.18.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-862: Missing Authorization

Membership Plugin <= 3.2.20 carries this weakness at rcp_setup_registration_init(), 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 Membership Plugin the fix is 3.2.21: builds <= 3.2.20 are affected, anything from 3.2.21 onward is not.

Remediation

Update to version 3.2.21, 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: Membership Plugin 3.2.21 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

Related records

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