CVE-2026-1650: MDJM Event Management Auth Bypass Flaw

CVE-2026-1650 Overview

The MDJM Event Management plugin for WordPress contains a Missing Authorization vulnerability (CWE-862) that allows unauthorized data modification. The vulnerability exists in the custom_fields_controller function across all versions up to and including 1.7.8.1. Due to a missing capability check, unauthenticated attackers can exploit this flaw to delete arbitrary custom event fields by manipulating the delete_custom_field and id parameters.

Critical Impact

Unauthenticated attackers can delete arbitrary custom event fields, potentially disrupting business operations and compromising data integrity for event management workflows.

Affected Products

• MDJM Event Management WordPress Plugin versions up to and including 1.7.8.1
• WordPress installations running vulnerable versions of the plugin
• Event management systems utilizing MDJM custom fields functionality

Discovery Timeline

• 2026-03-07 - CVE-2026-1650 published to NVD
• 2026-03-09 - Last updated in NVD database

Technical Details for CVE-2026-1650

Vulnerability Analysis

This vulnerability represents a classic Broken Access Control flaw where the custom_fields_controller function fails to verify user capabilities before executing sensitive operations. The function processes requests to manage custom event fields but does not authenticate whether the requesting user has administrative privileges. This allows any unauthenticated user to send crafted requests that trigger field deletion operations.

The vulnerable code path is located in includes/admin/pages/event-fields.php and can be accessed without requiring WordPress administrator authentication. When the delete_custom_field action is triggered with a corresponding id parameter, the function proceeds to delete the specified custom field without validating the request origin or user permissions.

Root Cause

The root cause is the absence of a capability check within the custom_fields_controller function. WordPress plugins handling administrative operations should implement proper authorization using functions like current_user_can() to verify that the requesting user possesses the required capabilities (such as manage_options or a custom capability). The MDJM Event Management plugin omits this essential security control, creating an authorization bypass condition.

Additionally, the function may lack proper nonce verification, which would normally protect against Cross-Site Request Forgery attacks and provide an additional layer of request validation.

Attack Vector

The vulnerability is exploitable over the network without requiring any authentication or user interaction. An attacker can craft HTTP requests targeting the WordPress AJAX handler or the plugin's admin endpoints with the delete_custom_field action and an arbitrary field id parameter.

The attack methodology involves:

1. Identifying a WordPress installation running the vulnerable MDJM Event Management plugin
2. Crafting a malicious request that targets the custom_fields_controller function
3. Specifying the delete_custom_field action along with the id of the custom field to delete
4. Submitting the request without any authentication credentials

Successful exploitation results in the deletion of targeted custom event fields, which may contain business-critical configuration data. For detailed technical analysis, refer to the Wordfence Vulnerability Report and the WordPress Plugin File Reference.

Detection Methods for CVE-2026-1650

Indicators of Compromise

• Unexpected deletion of custom event fields in the MDJM Event Management plugin
• Anomalous HTTP requests to WordPress AJAX endpoints containing delete_custom_field action parameters
• Web server logs showing unauthenticated requests to plugin administrative functions
• Missing or corrupted event field configurations in the WordPress database

Detection Strategies

• Monitor web application firewall (WAF) logs for requests containing delete_custom_field and id parameters from unauthenticated sessions
• Implement WordPress activity logging to track custom field modifications and deletions
• Configure intrusion detection rules to alert on suspicious AJAX requests to the MDJM plugin endpoints
• Review access logs for patterns of requests targeting /wp-admin/admin-ajax.php with MDJM-related action parameters

Monitoring Recommendations

• Enable WordPress audit logging to track all plugin administrative actions
• Configure real-time alerts for custom field deletion events in production environments
• Implement database integrity monitoring to detect unauthorized modifications to MDJM plugin tables
• Deploy endpoint detection solutions capable of monitoring WordPress plugin activity

How to Mitigate CVE-2026-1650

Immediate Actions Required

• Update the MDJM Event Management plugin to a patched version (versions after 1.7.8.1)
• Review WordPress activity logs for signs of exploitation
• Backup all custom event field configurations before applying updates
• Consider temporarily deactivating the plugin if immediate patching is not feasible

Patch Information

A security patch addressing this vulnerability is available through the WordPress plugin repository. The fix introduces proper capability checks in the custom_fields_controller function to ensure only authorized administrators can modify or delete custom event fields. For patch details, see the WordPress Plugin Changeset Details.

Workarounds

• Restrict access to WordPress admin AJAX endpoints using web server configuration rules
• Implement a web application firewall rule to block unauthenticated requests containing delete_custom_field parameters
• Use WordPress security plugins to add additional access control layers for plugin administrative functions
• Consider implementing IP-based access restrictions for administrative endpoints

# Apache .htaccess example to restrict AJAX endpoint access
<Files admin-ajax.php>
    <RequireAll>
        Require all denied
        Require ip 192.168.1.0/24
    </RequireAll>
</Files>