CVE-2025-6895 in Login Security Plugin
Summary
by MITRE • 07/26/2025
The Melapress Login Security plugin for WordPress is vulnerable to Authentication Bypass due to missing authorization within the get_valid_user_based_on_token() function in versions 2.1.0 to 2.1.1. This makes it possible for unauthenticated attackers who know an arbitrary user meta value to bypass authentication checks and log in as that user.
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Analysis
by VulDB Data Team • 07/26/2025
The Melapress Login Security plugin for WordPress presents a critical authentication bypass vulnerability that directly undermines the security posture of affected systems. This vulnerability exists within the get_valid_user_based_on_token() function and affects versions 2.1.0 through 2.1.1, creating a pathway for unauthenticated attackers to exploit the authentication mechanism. The flaw stems from insufficient authorization checks that should normally validate user credentials before granting access to protected resources. When an attacker possesses knowledge of a specific user meta value, they can leverage this information to circumvent the standard authentication process and assume the identity of that user. This represents a fundamental breakdown in the plugin's access control implementation, where the absence of proper validation allows arbitrary user impersonation. The vulnerability aligns with CWE-284 which addresses improper access control issues in software systems, specifically targeting weak authorization mechanisms that permit unauthorized access to protected resources.
The technical exploitation of this vulnerability occurs through manipulation of user meta values that are typically used for authentication token validation. The get_valid_user_based_on_token() function fails to properly verify that the requesting user has legitimate authorization to access the system, instead relying on potentially guessable or obtainable meta information. This creates a scenario where attackers can construct malicious requests that appear to originate from legitimate users, bypassing all standard authentication checks. The flaw essentially allows for session hijacking through meta value manipulation, where the system trusts the provided meta information without sufficient verification. This type of vulnerability falls under the ATT&CK technique T1078 which covers valid accounts and legitimate credentials for unauthorized access. The attack vector is particularly dangerous because it requires minimal reconnaissance to identify potentially exploitable user meta values, making it accessible to attackers with basic knowledge of the target environment.
The operational impact of this vulnerability extends beyond simple unauthorized access to potentially full system compromise. An attacker who successfully exploits this vulnerability can gain access to user accounts, potentially leading to data theft, account manipulation, and further privilege escalation within the WordPress environment. The affected plugin's authentication bypass capability could enable attackers to access sensitive user information, modify content, or even install malicious code through compromised user accounts. This vulnerability particularly threatens organizations that rely on the Melapress plugin for security, as it undermines the entire authentication framework that the plugin is designed to protect. The impact is amplified because the vulnerability affects a widely used WordPress plugin, potentially exposing numerous websites to unauthorized access. Organizations may face reputational damage, regulatory compliance issues, and potential legal consequences if user data is compromised through this vulnerability.
Organizations should immediately update to the latest version of the Melapress Login Security plugin where this vulnerability has been patched. The patch likely addresses the missing authorization checks within the get_valid_user_based_on_token() function by implementing proper validation of user credentials and meta value authenticity. System administrators should also conduct thorough security audits of their WordPress installations to identify any potential exploitation attempts. Additional mitigations include implementing network-level restrictions, monitoring for unusual authentication patterns, and ensuring that user meta values are properly secured and not easily guessable. The vulnerability highlights the importance of proper authorization implementation in web applications and serves as a reminder that authentication bypass flaws can have catastrophic consequences. Security teams should also consider implementing multi-factor authentication mechanisms as an additional layer of protection, as this can mitigate the impact of credential-based attacks even when authentication bypass vulnerabilities exist. Regular security assessments and vulnerability scanning should be performed to identify similar authorization flaws in other plugins and components of the WordPress ecosystem.