CVE-2026-4056

User Registration & Membership <= 5.1.4 - Missing Authorization to Authenticated (Contributor+) Content Access Rule Manipulation

2026-03-23 11:24
normaandersonfrank

At a glance

CVE-2026-4056 is a medium-severity Missing Authorization vulnerability in the User Registration & Membership WordPress plugin, affecting versions <= 5.1.4. It carries a CVSS score of 5.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 5.1.5; sites on affected versions should update now. Disclosed March 2026, reported by normaandersonfrank.

Vulnerability Overview

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.

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 interaction from a victim user.

CWE-862: Missing Authorization

User Registration & Membership <= 5.1.4 carries this weakness at check_permissions(), and reaching it takes an account at Contributor level or above. 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 5.1.5: builds <= 5.1.4 are affected, anything from 5.1.5 onward is not.

Remediation

Update to version 5.1.5, or a newer patched version

How does WordSec protect against this?

Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: User Registration & Membership 5.1.5 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

Related records

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