CVE-2026-23547: CMSMasters Content Composer Auth Bypass

CVE-2026-23547 Overview

A Missing Authorization vulnerability has been identified in the CMSMasters Content Composer WordPress plugin. This vulnerability allows attackers to exploit incorrectly configured access control security levels, potentially enabling unauthorized actions within WordPress installations using the affected plugin. The flaw is classified under CWE-862 (Missing Authorization), indicating that the plugin fails to properly verify that users have the necessary permissions before allowing certain operations.

Critical Impact

Unauthorized users may be able to perform privileged actions within WordPress sites running CMSMasters Content Composer versions through 2.5.8, potentially leading to content manipulation or site compromise.

Affected Products

• CMSMasters Content Composer WordPress Plugin versions n/a through <= 2.5.8

Discovery Timeline

• 2026-02-19 - CVE-2026-23547 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-23547

Vulnerability Analysis

This vulnerability stems from a Broken Access Control flaw within the CMSMasters Content Composer plugin for WordPress. The plugin fails to implement proper authorization checks on certain functionality, allowing users without appropriate privileges to access or execute restricted operations.

Missing Authorization vulnerabilities (CWE-862) occur when software does not perform an authorization check when an actor attempts to access a resource or perform an action. In the context of WordPress plugins, this typically manifests when plugin functions that should be restricted to administrators or editors can be accessed by lower-privileged users, including unauthenticated visitors in some cases.

Root Cause

The root cause of CVE-2026-23547 is the absence of proper capability checks within the CMSMasters Content Composer plugin. WordPress provides a robust capabilities system that allows developers to verify user permissions before executing sensitive operations. When these checks are missing or improperly implemented, unauthorized users can bypass intended access restrictions.

This type of flaw often occurs when plugin developers rely on page-level restrictions or obscurity rather than implementing proper current_user_can() checks within AJAX handlers, REST API endpoints, or administrative functions.

Attack Vector

An attacker can exploit this vulnerability by directly accessing plugin functions that lack proper authorization verification. The attack typically involves:

1. Identifying unprotected AJAX actions or REST endpoints exposed by the plugin
2. Crafting requests to these endpoints without the required authentication or authorization headers
3. Executing privileged operations such as modifying content, accessing sensitive data, or altering plugin settings

Since the vulnerability relates to broken access control, exploitation does not require advanced technical skills once the vulnerable endpoints are identified. For detailed technical information, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2026-23547

Indicators of Compromise

• Unexpected changes to WordPress content or settings not attributable to authorized users
• Unusual API or AJAX requests to CMSMasters Content Composer plugin endpoints from unauthenticated sessions
• Access logs showing requests to plugin-specific endpoints from external IP addresses
• Modifications to content composer elements without corresponding administrator activity

Detection Strategies

• Monitor WordPress access logs for suspicious requests targeting /wp-admin/admin-ajax.php with CMSMasters-related action parameters
• Implement Web Application Firewall (WAF) rules to detect and block unauthorized access attempts to plugin endpoints
• Review WordPress audit logs for content changes made by unexpected user roles
• Deploy endpoint detection solutions capable of monitoring WordPress plugin activity

Monitoring Recommendations

• Enable detailed logging for WordPress AJAX requests and REST API calls
• Set up alerts for failed authorization attempts or access from unexpected user roles
• Regularly audit user activity logs for anomalous behavior patterns
• Monitor plugin directories for unauthorized file modifications

How to Mitigate CVE-2026-23547

Immediate Actions Required

• Update CMSMasters Content Composer to a patched version when available from the vendor
• If no patch is available, consider temporarily disabling the plugin until a fix is released
• Implement additional access controls at the web server or WAF level to restrict access to plugin endpoints
• Review and audit current WordPress user roles and remove unnecessary privileges
• Monitor site activity for signs of exploitation

Patch Information

Consult the Patchstack Vulnerability Report for the latest patch availability and vendor guidance. Users should update to a version newer than 2.5.8 once the vendor releases a security fix.

Workarounds

• Implement WordPress capability checks at the theme or custom plugin level to validate user permissions before CMSMasters Content Composer functions execute
• Use a security plugin such as Wordfence or Sucuri to add additional access control layers
• Restrict access to wp-admin/admin-ajax.php for unauthenticated users if feasible for your site configuration
• Consider implementing IP-based access restrictions for administrative functions

# Example .htaccess restriction for admin-ajax.php (use with caution)
# This may break legitimate AJAX functionality for frontend users
<Files admin-ajax.php>
    Order Deny,Allow
    Deny from all
    Allow from 192.168.1.0/24
    # Add trusted IP ranges as needed
</Files>