CVE-2023-2027 in ZM Ajax Login & Register Plugin
Summary
by MITRE • 04/15/2023
The ZM Ajax Login & Register plugin for WordPress is vulnerable to authentication bypass in versions up to, and including, 2.0.2. This is due to insufficient verification on the user being supplied during a Facebook login through the plugin. This makes it possible for unauthenticated attackers to log in as any existing user on the site, such as an administrator, if they have access to the username.
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Analysis
by VulDB Data Team • 04/09/2026
The vulnerability identified as CVE-2023-2027 affects the ZM Ajax Login & Register plugin for WordPress, specifically targeting versions up to and including 2.0.2. This authentication bypass flaw represents a critical security weakness that fundamentally undermines the plugin's ability to verify user identities during Facebook login operations. The vulnerability stems from inadequate validation mechanisms that fail to properly authenticate the user account being supplied during the social login process, creating a pathway for malicious actors to exploit the system's trust model.
The technical flaw manifests in the plugin's insufficient verification procedures during Facebook authentication flows, where the system does not adequately validate the identity of users attempting to log in through the social login mechanism. This weakness allows attackers to manipulate the authentication process by supplying fabricated user data or leveraging predictable patterns in the login flow. The vulnerability is particularly dangerous because it enables unauthenticated attackers to assume the identity of any existing user account on the WordPress site, including high-privilege administrators, provided they possess knowledge of valid usernames. This represents a classic case of insufficient input validation and authentication checks that violates fundamental security principles.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with unauthorized access to WordPress administrative functions and user data. An attacker who can enumerate valid usernames can leverage this vulnerability to gain complete control over targeted accounts, potentially leading to full site compromise, data exfiltration, or malicious modifications to website content. The vulnerability's exploitation requires minimal technical skill beyond basic username enumeration, making it particularly dangerous in environments where user account information might be publicly accessible or easily discoverable through various reconnaissance techniques. This authentication bypass creates a persistent threat that can be exploited repeatedly without requiring additional authentication factors or complex attack vectors.
The vulnerability aligns with CWE-287, which addresses improper authentication issues in software systems, and corresponds to tactics in the MITRE ATT&CK framework under T1110, specifically credential access through exploitation of weak or flawed authentication mechanisms. Organizations affected by this vulnerability should immediately update to the latest version of the plugin where the authentication bypass has been patched. The recommended mitigation includes implementing strong account lockout mechanisms, enforcing multi-factor authentication, and conducting thorough security audits of all WordPress plugins to ensure proper authentication handling. Additionally, administrators should consider implementing network-level protections such as rate limiting and IP-based restrictions to limit the potential impact of credential stuffing attacks that could exploit this vulnerability.