CVE-2026-107254 in Authenticator Login Plus Plugin
Summary
by MITRE • 10/30/2026
Authentication Bypass Using an Alternate Path or Channel vulnerability in Drupal Authenticator Login Plus (2FA) allows Authentication Bypass. This issue affects Authenticator Login Plus (2FA) versions: from 0.0.0 to 1.0.1.
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Analysis
by VulDB Data Team • 10/30/2026
The vulnerability identified within the Drupal module Authenticator Login Plus, specifically in versions ranging from 0.0.0 through 1.0.1, represents a critical authentication bypass flaw that undermines the integrity of two-factor authentication mechanisms. This issue is classified under CWE-287, which denotes Improper Authentication, and aligns with MITRE ATT&CK technique T1078, Valid Accounts, as it allows an attacker to gain unauthorized access by circumventing established security controls. The core technical flaw lies in the module's handling of authentication requests across different paths or channels within the Drupal application framework. Instead of enforcing a consistent verification state for all entry points, the implementation fails to properly validate whether two-factor authentication has been successfully completed when accessing certain alternative routes or API endpoints that bypass the standard login form flow.
In a secure two-factor authentication system, once a user provides their primary credentials and completes the secondary factor validation, this authenticated state must be persistently enforced across all subsequent requests until logout occurs. However, in the affected versions of Authenticator Login Plus, there exists an alternate path or channel where the application logic does not adequately check for the presence of valid two-factor authentication tokens or session flags before granting access to protected resources. This architectural oversight creates a gap where an attacker can bypass the secondary verification step entirely by interacting directly with specific endpoints that do not trigger the necessary security checks associated with the primary login process. Consequently, possession of valid user credentials alone becomes sufficient for full system compromise, rendering the two-factor authentication feature ineffective against targeted attacks.
The operational impact of this vulnerability is severe, as it effectively nullifies one of the most effective defenses against credential theft and brute force attacks. If an attacker obtains a user's password through phishing, data breaches, or keylogging, they can immediately access sensitive Drupal administrative interfaces or private content without needing to compromise the second factor, such as a time-based one-time password generated by a mobile authenticator app. This significantly lowers the barrier for entry and increases the likelihood of successful unauthorized access in environments where two-factor authentication is deployed under the assumption that it provides robust protection against compromised passwords. The vulnerability affects all installations using versions up to 1.0.1, meaning any site relying on this module for enhanced security may be operating with a false sense of safety regarding account compromise scenarios.
Mitigation strategies must prioritize immediate remediation through software updates and configuration adjustments. The primary recommendation is to upgrade the Authenticator Login Plus module to version 1.0.2 or later, where developers have addressed the path validation logic to ensure that all authentication checks are consistently applied regardless of the entry point used by the client application. In cases where an immediate update is not feasible due to compatibility constraints with other modules or custom code modifications, administrators should implement compensating controls such as web application firewall rules that restrict access to sensitive endpoints based on IP reputation or behavioral anomalies. Additionally, enforcing strict session management policies and monitoring for unusual login patterns can help detect potential exploitation attempts while the patching process is underway. Regular security audits of authentication flows across all module interactions are essential to prevent similar bypass vectors from being introduced in future updates.