CVE-2025-13986 Overview
CVE-2025-13986 is an Authentication Bypass Using an Alternate Path or Channel vulnerability (CWE-288) affecting the Drupal Disable Login Page module. This security flaw allows attackers to bypass authentication mechanisms through an alternate path or channel, effectively circumventing the intended security controls implemented by the module. The vulnerability enables functionality bypass, allowing unauthorized access to protected resources that should be restricted by the login page disabling feature.
Critical Impact
Attackers can bypass authentication controls in the Drupal Disable Login Page module, potentially gaining unauthorized access to sensitive information or protected functionality on affected Drupal installations.
Affected Products
- Drupal Disable Login Page module versions from 0.0.0 before 1.1.3
Discovery Timeline
- 2026-01-28 - CVE CVE-2025-13986 published to NVD
- 2026-01-29 - Last updated in NVD database
Technical Details for CVE-2025-13986
Vulnerability Analysis
This vulnerability falls under CWE-288 (Authentication Bypass Using an Alternate Path or Channel), which occurs when a product requires authentication but provides an alternate path or channel that does not require authentication. In the context of the Drupal Disable Login Page module, the intended functionality is to disable or restrict access to the standard login page. However, the vulnerability allows attackers to circumvent this protection by accessing authentication mechanisms through an unprotected alternate route.
The attack can be executed remotely over the network without requiring any prior authentication or user interaction, making it particularly dangerous for publicly accessible Drupal installations that rely on this module for access control.
Root Cause
The root cause of this vulnerability lies in incomplete access control implementation within the Drupal Disable Login Page module. The module fails to adequately protect all authentication entry points, leaving alternate paths or channels accessible even when the primary login page is disabled. This oversight allows attackers to discover and exploit these unprotected routes to bypass the intended authentication restrictions.
Attack Vector
The attack vector for CVE-2025-13986 is network-based, requiring no authentication or user interaction. An attacker can exploit this vulnerability by:
- Identifying a Drupal installation using the vulnerable Disable Login Page module
- Discovering alternate authentication paths or channels that bypass the disabled login page
- Accessing the unprotected route to bypass authentication controls
- Gaining unauthorized access to sensitive information or protected functionality
The vulnerability allows for high confidentiality impact, potentially exposing sensitive data that should be protected behind authentication. For detailed technical information about the vulnerability and exploitation methods, refer to the Drupal Security Advisory.
Detection Methods for CVE-2025-13986
Indicators of Compromise
- Unusual authentication attempts or successful logins through non-standard URL paths
- Access logs showing requests to alternate login endpoints that should be disabled
- Unexpected session creation events without corresponding standard login page activity
- Authentication events from IP addresses or user agents not associated with legitimate users
Detection Strategies
- Monitor web server access logs for requests to authentication-related endpoints that bypass the standard login page
- Implement web application firewall (WAF) rules to detect and alert on authentication bypass attempts
- Review Drupal watchdog logs for anomalous authentication events or session creation patterns
- Configure intrusion detection systems to alert on unexpected access patterns to protected resources
Monitoring Recommendations
- Enable comprehensive logging for all authentication-related activities in Drupal
- Set up real-time alerting for authentication events from unexpected sources or paths
- Regularly audit user sessions and access patterns to identify potential unauthorized access
- Monitor for reconnaissance activities targeting alternate authentication endpoints
How to Mitigate CVE-2025-13986
Immediate Actions Required
- Update the Drupal Disable Login Page module to version 1.1.3 or later immediately
- Audit access logs to identify any potential exploitation attempts prior to patching
- Review user accounts and sessions for signs of unauthorized access
- Consider temporarily disabling the vulnerable module until the patch can be applied
Patch Information
The vulnerability has been addressed in Drupal Disable Login Page module version 1.1.3. Site administrators should update to this version or later as soon as possible. The security advisory is available at the Drupal Security Advisory page.
To update the module using Composer:
# Update the Disable Login Page module to the patched version
composer update drupal/disable_login_page
# Clear Drupal cache after update
drush cr
Workarounds
- Temporarily disable the Disable Login Page module if immediate patching is not possible
- Implement additional access controls at the web server or reverse proxy level to restrict authentication endpoints
- Use a Web Application Firewall (WAF) to block requests to known alternate authentication paths
- Enable IP-based access restrictions for administrative and authentication functions
# Configuration example - Apache .htaccess to restrict authentication paths
# Add to your Drupal .htaccess file
<FilesMatch "^(user|login|admin)">
Order Deny,Allow
Deny from all
Allow from 192.168.1.0/24
Allow from 10.0.0.0/8
</FilesMatch>
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
