CVE-2026-5529: Dromara lamp-cloud Auth Bypass Vulnerability

CVE-2026-5529 Overview

A vulnerability has been identified in Dromara lamp-cloud versions up to 5.8.1 that affects the pageUser function within the /defUser/pageUser endpoint of the DefUserController component. This improper authorization vulnerability allows remote attackers to bypass access controls and potentially access user data without proper privileges.

Critical Impact

Remote attackers can exploit this improper authorization flaw to access the pageUser functionality without appropriate permissions, potentially exposing sensitive user information through the DefUserController endpoint.

Affected Products

• Dromara lamp-cloud up to version 5.8.1
• DefUserController component (/defUser/pageUser endpoint)
• Applications utilizing the pageUser function

Discovery Timeline

• 2026-04-05 - CVE CVE-2026-5529 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2026-5529

Vulnerability Analysis

This vulnerability is classified as CWE-266 (Incorrect Privilege Assignment), indicating that the application fails to properly enforce authorization checks on the pageUser function. The DefUserController exposes the /defUser/pageUser endpoint without adequate verification of user privileges, allowing authenticated users with low-level access to perform actions that should be restricted to higher-privileged accounts.

The vulnerability is exploitable remotely over the network with low attack complexity. An attacker with basic authentication credentials can manipulate requests to the vulnerable endpoint and gain unauthorized access to user listing and pagination functionality that should be protected by proper authorization controls.

Root Cause

The root cause lies in the DefUserController's failure to implement proper authorization checks before executing the pageUser function. The application does not adequately validate whether the requesting user has sufficient privileges to access user data through this endpoint, resulting in an improper authorization condition.

Attack Vector

The attack can be initiated remotely over the network by any authenticated user with low-level privileges. The attacker sends a crafted request to the /defUser/pageUser endpoint, which processes the request without verifying the user's authorization level. This allows unauthorized access to user pagination data that should be restricted.

The vulnerability exists because the pageUser function in DefUserController does not perform adequate privilege checks before returning results. An attacker can simply authenticate with minimal credentials and access the endpoint directly to retrieve user information. For technical details, see GitHub Issue #403.

Detection Methods for CVE-2026-5529

Indicators of Compromise

• Unusual access patterns to the /defUser/pageUser endpoint from low-privileged accounts
• Increased volume of requests to DefUserController endpoints from unexpected user sessions
• Audit log entries showing user enumeration activities by non-administrative accounts

Detection Strategies

• Implement logging and monitoring for all requests to the /defUser/pageUser endpoint
• Deploy Web Application Firewall (WAF) rules to detect abnormal access patterns to user management endpoints
• Review access control configurations for DefUserController to identify misconfigured permissions

Monitoring Recommendations

• Enable detailed audit logging for all DefUserController endpoints
• Monitor authentication logs for users accessing administrative functions without proper role assignments
• Set up alerts for repeated access to user pagination endpoints from non-privileged accounts

How to Mitigate CVE-2026-5529

Immediate Actions Required

• Restrict access to the /defUser/pageUser endpoint to only authorized administrative users
• Implement additional authentication and authorization checks in the DefUserController
• Review and audit all user roles and permissions within lamp-cloud deployments
• Consider temporarily disabling the vulnerable endpoint until a patch is available

Patch Information

At the time of this publication, the vendor has not yet released an official patch. The project was informed of the vulnerability through GitHub Issue #403 but has not responded. Users should monitor the lamp-cloud GitHub repository for security updates and patch releases.

Workarounds

• Implement network-level access controls to restrict access to the /defUser/pageUser endpoint
• Add custom authorization middleware to validate user privileges before processing DefUserController requests
• Configure reverse proxy rules to block unauthorized access to user management endpoints

# Example: Nginx configuration to restrict access to vulnerable endpoint
location /defUser/pageUser {
    # Allow only from trusted administrative IPs
    allow 10.0.0.0/8;
    deny all;
    
    # Alternatively, require specific authentication headers
    if ($http_x_admin_token != "your-secure-token") {
        return 403;
    }
    
    proxy_pass http://backend;
}