CVE-2025-31673: Drupal Core Auth Bypass Vulnerability

CVE-2025-31673 Overview

CVE-2025-31673 is an Incorrect Authorization vulnerability affecting Drupal core that enables Forceful Browsing attacks. This authorization bypass flaw allows authenticated attackers to access resources and functionality that should be restricted based on their permission level. The vulnerability impacts multiple versions of Drupal core across the 8.x, 10.x, and 11.x branches.

Critical Impact

Authenticated users can bypass authorization controls to access restricted content and functionality through forceful browsing techniques, potentially exposing sensitive data or administrative features.

Affected Products

• Drupal core versions 8.0.0 through 10.3.12
• Drupal core versions 10.4.0 through 10.4.2
• Drupal core versions 11.0.0 through 11.0.11
• Drupal core versions 11.1.0 through 11.1.2

Discovery Timeline

• March 31, 2025 - CVE-2025-31673 published to NVD
• June 2, 2025 - Last updated in NVD database

Technical Details for CVE-2025-31673

Vulnerability Analysis

This vulnerability is classified as CWE-863 (Incorrect Authorization), which occurs when software does not properly verify that a user is authorized to access a resource or perform an action. In the context of Drupal core, this manifests as insufficient authorization checks that allow authenticated users to access content or functionality beyond their assigned permissions.

The network-based attack vector requires low attack complexity but does require the attacker to have valid credentials (low privileges) and some user interaction. When successfully exploited, the vulnerability can result in unauthorized access to confidential information and potential modification of data, though availability is not impacted.

Root Cause

The root cause of CVE-2025-31673 lies in improper authorization validation within Drupal core's access control mechanisms. The vulnerability stems from inadequate permission checks that fail to properly verify whether an authenticated user should have access to specific resources or endpoints. This allows attackers to directly navigate to URLs or manipulate requests to access resources that should be protected by role-based access controls.

Attack Vector

The attack is conducted over the network and leverages forceful browsing techniques. An attacker with valid credentials can exploit this vulnerability by:

1. Authenticating to the Drupal site with a low-privilege account
2. Manually crafting or navigating to URLs that reference restricted resources
3. Bypassing normal navigation flows to access content or functionality that should require elevated permissions

The vulnerability requires user interaction, suggesting the attack may involve social engineering components or require specific user actions to complete the exploitation chain. Successful exploitation can lead to unauthorized read access to restricted content and limited integrity impact through potential data modification.

Detection Methods for CVE-2025-31673

Indicators of Compromise

• Unexpected access log entries showing low-privilege users accessing administrative or restricted URL paths
• Anomalous patterns of direct URL access bypassing normal navigation flows
• Authentication logs showing users accessing resources inconsistent with their role assignments

Detection Strategies

• Implement web application firewall rules to detect and alert on forceful browsing patterns
• Configure access logging to capture and analyze requests to sensitive endpoints
• Deploy anomaly detection to identify users accessing content outside their typical permission scope
• Review audit logs for authorization failures followed by successful access to the same resources

Monitoring Recommendations

• Enable verbose access logging on Drupal installations to track resource access patterns
• Monitor for HTTP 403 responses followed by attempts to access the same resources through alternative paths
• Implement real-time alerting for access attempts to administrative endpoints by non-admin users
• Regularly review user permission assignments against access logs to identify potential abuse

How to Mitigate CVE-2025-31673

Immediate Actions Required

• Update Drupal core to patched versions: 10.3.13, 10.4.3, 11.0.12, or 11.1.3 immediately
• Review access logs for evidence of exploitation prior to patching
• Audit user accounts and permissions to ensure principle of least privilege
• Consider temporarily restricting access to sensitive functionality until patches are applied

Patch Information

Drupal has released security updates addressing this vulnerability. Organizations should upgrade to the following patched versions:

For detailed patch information and installation instructions, refer to the Drupal Security Advisory 2025-002.

Workarounds

• Implement additional access control layers at the web server or reverse proxy level
• Use web application firewall rules to restrict access to sensitive endpoints based on user roles
• Temporarily disable or limit access to functionality that may be affected until patching is complete
• Enable additional logging and monitoring to detect exploitation attempts

# Example: Verify Drupal version to confirm patch status
drush status | grep "Drupal version"

# Update Drupal core using Composer
composer update drupal/core --with-dependencies

# Clear caches after update
drush cache:rebuild