CVE-2026-4562: MacCMS Authentication Bypass Vulnerability

CVE-2026-4562 Overview

A missing authentication vulnerability has been discovered in MacCMS 2025.1000.4052 affecting the Timming API endpoint. This security flaw exists within the application/api/controller/Timming.php file, where improper authentication controls allow unauthorized access to API functionality. The vulnerability can be exploited remotely over the network without requiring user interaction or special privileges, potentially enabling attackers to access or manipulate data through the unprotected endpoint.

Critical Impact

Remote attackers can bypass authentication controls to access the Timming API endpoint, potentially leading to unauthorized data access, modification, or system manipulation. The exploit has been publicly released and may already be used in active attacks.

Affected Products

• MacCMS 2025.1000.4052
• MacCMS Timming API (application/api/controller/Timming.php)

Discovery Timeline

• 2026-03-23 - CVE-2026-4562 published to NVD
• 2026-03-23 - Last updated in NVD database

Technical Details for CVE-2026-4562

Vulnerability Analysis

This vulnerability falls under CWE-287 (Improper Authentication), indicating that the affected component fails to properly verify the identity of users before granting access to protected resources. The Timming API endpoint in MacCMS does not implement adequate authentication mechanisms, allowing unauthenticated remote attackers to interact with the API directly.

The flaw resides specifically in the Timming.php controller file within the application's API directory structure. Without proper authentication gates, any network-accessible request to this endpoint will be processed regardless of the requester's authorization status. This architectural oversight is particularly dangerous in content management systems where APIs often control sensitive administrative or data management functions.

Root Cause

The root cause of CVE-2026-4562 is the absence of authentication checks in the Timming API controller. The application/api/controller/Timming.php file processes incoming API requests without validating whether the requester has been properly authenticated or authorized to perform the requested actions. This missing authentication control violates the principle of defense in depth and represents a fundamental access control failure in the application architecture.

Attack Vector

The attack vector for this vulnerability is network-based, requiring no authentication, no user interaction, and low attack complexity. An attacker can exploit this vulnerability by directly sending crafted HTTP requests to the Timming API endpoint from any network location that can reach the vulnerable MacCMS installation.

The exploitation process involves identifying MacCMS installations running the vulnerable version, locating the exposed Timming API endpoint, and sending unauthenticated requests to access or manipulate data through the unprotected API functionality. The public availability of exploit information increases the risk of widespread exploitation.

Detection Methods for CVE-2026-4562

Indicators of Compromise

• Unusual or unexpected HTTP requests targeting /application/api/controller/Timming.php or the Timming API routes
• Access logs showing API calls to Timming endpoints from unauthorized IP addresses or without valid session tokens
• Anomalous data modifications or access patterns associated with Timming API functionality
• Increased traffic volume to API endpoints from external sources

Detection Strategies

• Monitor web server access logs for requests to the Timming API endpoint without accompanying authentication headers or valid session cookies
• Implement web application firewall (WAF) rules to detect and alert on unauthenticated API access attempts
• Deploy intrusion detection systems (IDS) with signatures for known MacCMS exploitation patterns
• Conduct periodic security audits of MacCMS API access patterns and authentication enforcement

Monitoring Recommendations

• Enable detailed logging for all API endpoints in MacCMS, particularly the Timming controller
• Set up real-time alerting for API requests that bypass authentication middleware
• Monitor for reconnaissance activities targeting MacCMS version fingerprinting
• Track failed and successful API authentication attempts for anomaly detection

How to Mitigate CVE-2026-4562

Immediate Actions Required

• Restrict network access to the Timming API endpoint using firewall rules or web server configuration until a patch is available
• Implement authentication middleware or access controls at the web server level for the affected endpoint
• Review and audit all API endpoints in the MacCMS installation for similar authentication bypass vulnerabilities
• Consider temporarily disabling the Timming API functionality if it is not critical to operations

Patch Information

As of the last NVD update on 2026-03-23, no official vendor patch has been documented. Organizations should monitor the GitHub CVE Issue Discussion and VulDB entry for updates on remediation guidance. Contact the MacCMS maintainers directly for patch availability information.

Workarounds

• Apply web server access controls (.htaccess or nginx configuration) to restrict access to the Timming API endpoint to trusted IP addresses only
• Implement a reverse proxy with authentication requirements in front of the MacCMS API endpoints
• Use a Web Application Firewall (WAF) to enforce authentication checks before requests reach the vulnerable endpoint
• Disable or remove the Timming.php controller if the functionality is not required for your deployment

# Example: Restrict access to Timming API via nginx configuration
location ~ /api/.*Timming {
    # Deny all external access
    deny all;
    # Or restrict to trusted IPs only
    # allow 192.168.1.0/24;
    # deny all;
}