CVE intelligence and bounded remediation

CVE-2026-1321 — Membership Plugin security vulnerability

High CVSS 8.1

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.

Severity
High
CVSS
8.1 (3.1)
Published
2026-03-05
CISA KEV
Not currently listed
Ecosystem
php/wordpress
Weaknesses
CWE-862

Affected products

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Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

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Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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