Overview
The cybersecurity industry has recently been alerted to a critical vulnerability, CVE-2025-2594, which affects the User Registration & Membership WordPress Plugin (versions prior to 4.1.3). This vulnerability poses a significant risk, as it allows potential attackers to authenticate as any user, including administrators, by simply using the target account’s user ID.
This vulnerability is especially concerning given the popularity of WordPress and its wide use in creating websites globally. The potential risk of system compromise or data leakage is significant, and all users of the affected plugin should be aware and take immediate steps to mitigate this risk.
Vulnerability Summary
CVE ID: CVE-2025-2594
Severity: Critical (CVSS: 8.1)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Unauthorized access to user accounts, including admin accounts, potential system compromise, and data leakage
Affected Products
No phone number, email, or personal info required.
Product | Affected Versions
User Registration & Membership WordPress Plugin | < 4.1.3 How the Exploit Works
The vulnerability stems from the lack of proper data validation in an AJAX action when the Membership Addon is enabled. As a result, an attacker can exploit this flaw by using a crafted AJAX request with the target account’s user ID. This effectively bypasses the authentication process, granting the attacker the same level of access as the targeted user, including potentially full administrative access if the targeted user is an administrator.
Conceptual Example Code
Below is a conceptual example of how an attacker might exploit this vulnerability. This example assumes that the attacker already knows the user ID of the target account:
POST /wp-admin/admin-ajax.php HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
action=ur_ajax_login&user_id=1In this example, ‘ur_ajax_login’ is the AJAX action exploited, and ‘user_id=1’ represents an attempt to authenticate as the user with the ID ‘1’, which is typically the administrator account in a WordPress installation.
Mitigation Guidance
Given the critical nature of this vulnerability, it is highly recommended for users to immediately update the User Registration & Membership plugin to version 4.1.3 or later, as the vendor has already issued a patch addressing this issue.
In cases where an immediate update is not possible, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) could serve as temporary mitigation. These systems can be configured to detect and block malicious AJAX requests exploiting this vulnerability. However, this is only a temporary solution, and updating the plugin should be the priority to ensure long-term security.