CVE-2023-2440 in UserPro Plugin
Summary
by MITRE • 11/22/2023
The UserPro plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 5.1.1. This is due to missing nonce validation in the 'admin_page', 'userpro_verify_user' and 'verifyUnverifyAllUsers' functions. This makes it possible for unauthenticated attackers to modify the role of verified users to elevate verified user privileges to that of any user such as 'administrator' via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
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Analysis
by VulDB Data Team • 04/11/2026
The CVE-2023-2440 vulnerability affects the UserPro plugin for WordPress, a popular user management solution that handles user registration, verification, and role assignment functionalities. This vulnerability represents a critical security flaw that undermines the integrity of user privilege management within WordPress installations. The issue stems from insufficient validation mechanisms within the plugin's administrative functions, creating a pathway for unauthorized privilege escalation attacks. The vulnerability specifically impacts versions up to and including 5.1.1, making a significant portion of WordPress installations potentially vulnerable if they have not updated to newer versions. The flaw exists in the core administrative functions that handle user verification processes, which are essential components for maintaining secure user access controls.
The technical implementation of this vulnerability lies in the absence of proper nonce validation within three critical functions: 'admin_page', 'userpro_verify_user', and 'verifyUnverifyAllUsers'. A nonce is a cryptographic value that ensures requests originate from legitimate administrative actions and helps prevent unauthorized modifications to user permissions. Without this validation, attackers can craft malicious requests that appear to come from authenticated administrators. The vulnerability operates through a cross-site request forgery mechanism where an attacker can manipulate user roles by sending forged requests to the WordPress admin interface. When a site administrator clicks on a malicious link or visits a compromised page, their browser automatically submits a request that modifies user privileges without their knowledge or consent. This type of attack leverages the trust relationship between the browser and the WordPress admin interface, exploiting the fact that the system does not verify the authenticity of the request source.
The operational impact of this vulnerability is severe and far-reaching for WordPress site administrators and their users. An unauthenticated attacker who successfully tricks an administrator into performing a malicious action can elevate verified users to administrator privileges, completely compromising the site's security posture. This privilege escalation allows attackers to gain complete control over the WordPress installation, including the ability to modify content, install malicious plugins, access sensitive user data, and potentially use the compromised site as a launching point for further attacks against other systems. The vulnerability particularly affects sites that rely heavily on user verification processes and role-based access controls, as it undermines the fundamental security assumptions that protect these systems. Additionally, the attack requires minimal technical expertise, making it accessible to threat actors with basic knowledge of web application security principles. The impact extends beyond immediate privilege escalation to potential data breaches, content manipulation, and service disruption.
Mitigation strategies for CVE-2023-2440 should prioritize immediate plugin updates to versions that address the nonce validation deficiencies. Site administrators must ensure they are running the latest version of the UserPro plugin, which should include proper nonce validation mechanisms for all administrative functions. Regular security audits and monitoring of plugin installations are essential to prevent similar vulnerabilities from being introduced. The implementation of additional security measures such as two-factor authentication for administrative accounts, restricted access controls, and regular security scanning can provide defense-in-depth against similar attacks. Organizations should also implement web application firewalls to detect and block suspicious requests that attempt to manipulate user roles. From a compliance perspective, this vulnerability aligns with CWE-352, which addresses Cross-Site Request Forgery vulnerabilities, and maps to ATT&CK technique T1078.004 for Valid Accounts and T1548.003 for Abuse of Cloud Infrastructure, highlighting the need for comprehensive security controls. System administrators should also establish incident response procedures to quickly identify and remediate any potential exploitation attempts. The vulnerability underscores the importance of maintaining current security practices and the necessity of validating all administrative functions through proper authentication mechanisms.