CVE intelligence and bounded remediation

CVE-2026-4056 — User Registration & Membership security vulnerability

Medium CVSS 5.4

The User Registration & Membership plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the Content Access Rules REST API endpoints in versions 5.0.1 through 5.1.4. This is due to the `check_permissions()` method only checking for `edit_posts` capability instead of an administrator-level capability. This makes it possible for authenticated attackers, with Contributor-level access and above, to list, create, modify, toggle, duplicate, and delete site-wide content restriction rules, potentially exposing restricted content or denying legitimate user access.

Severity
Medium
CVSS
5.4 (3.1)
Published
2026-03-24
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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