CVE-2025-6440: WooCommerce Designer Pro RCE Vulnerability

CVE-2025-6440 Overview

The WooCommerce Designer Pro plugin for WordPress, commonly used with the Pricom - Printing Company & Design Services WordPress theme, contains an arbitrary file upload vulnerability due to missing file type validation in the wcdp_save_canvas_design_ajax function. This vulnerability affects all versions up to and including 1.9.26 and allows unauthenticated attackers to upload arbitrary files to the affected site's server, potentially enabling remote code execution.

Critical Impact

Unauthenticated remote attackers can upload malicious files (such as PHP webshells) to WordPress servers, leading to complete server compromise and remote code execution without any authentication required.

Affected Products

• WooCommerce Designer Pro plugin versions up to and including 1.9.26
• WordPress sites using the Pricom - Printing Company & Design Services theme
• Any WordPress installation with the vulnerable WooCommerce Designer Pro plugin

Discovery Timeline

• 2025-10-24 - CVE-2025-6440 published to NVD
• 2025-10-27 - Last updated in NVD database

Technical Details for CVE-2025-6440

Vulnerability Analysis

This vulnerability is classified as CWE-434 (Unrestricted Upload of File with Dangerous Type). The core issue lies in the wcdp_save_canvas_design_ajax function within the WooCommerce Designer Pro plugin, which fails to implement proper file type validation before accepting uploaded files. This design flaw allows attackers to bypass intended upload restrictions and place arbitrary files on the server's filesystem.

The vulnerability is particularly severe because it requires no authentication to exploit. Any remote attacker with network access to the WordPress installation can craft malicious requests to the vulnerable AJAX endpoint and upload files of their choosing, including executable PHP scripts.

Root Cause

The root cause of this vulnerability is the absence of file type validation in the wcdp_save_canvas_design_ajax AJAX handler function. The plugin fails to verify that uploaded files match expected types (such as images for design canvases) before writing them to the server. Without proper validation of file extensions, MIME types, and file content, attackers can upload dangerous file types that the server may execute.

Attack Vector

The attack leverages the network-accessible AJAX endpoint exposed by the vulnerable plugin. An unauthenticated attacker can send a specially crafted POST request to the WordPress AJAX handler (wp-admin/admin-ajax.php) targeting the wcdp_save_canvas_design_ajax action. By including a malicious PHP file in the request body, the attacker can upload a webshell or other malicious script directly to the server.

Once the malicious file is uploaded, the attacker can execute arbitrary commands on the server by accessing the uploaded file via its URL, achieving full remote code execution. This attack requires no user interaction and can be fully automated.

The vulnerability mechanism involves crafting a multipart form request to the WordPress AJAX endpoint with the wcdp_save_canvas_design_ajax action parameter. Since the function lacks file type validation, malicious PHP payloads pass through unfiltered and are written to the server's upload directory. For detailed technical analysis, refer to the Wordfence Vulnerability Analysis.

Detection Methods for CVE-2025-6440

Indicators of Compromise

• Unexpected PHP files appearing in WordPress upload directories, particularly within the WooCommerce Designer Pro upload paths
• Web server logs showing POST requests to admin-ajax.php with the action parameter wcdp_save_canvas_design_ajax from unfamiliar IP addresses
• Presence of webshell files with suspicious names or obfuscated PHP code in upload directories
• Unusual outbound network connections originating from the web server process

Detection Strategies

• Monitor WordPress AJAX endpoints for requests containing the wcdp_save_canvas_design_ajax action, especially from unauthenticated sessions
• Implement file integrity monitoring to detect new or modified PHP files in upload directories
• Deploy web application firewall (WAF) rules to inspect file upload requests for dangerous file extensions and content
• Review web server access logs for patterns consistent with webshell access, such as requests to unusual PHP files in upload directories

Monitoring Recommendations

• Enable detailed logging for WordPress AJAX requests and file upload operations
• Configure alerts for any PHP file creation events within the wp-content/uploads directory tree
• Monitor for process spawning from the web server (e.g., Apache or Nginx spawning shell processes)
• Implement network monitoring for command-and-control traffic patterns from web servers

How to Mitigate CVE-2025-6440

Immediate Actions Required

• Update WooCommerce Designer Pro plugin to a patched version newer than 1.9.26 immediately
• If no patch is available, disable or remove the WooCommerce Designer Pro plugin until a fix is released
• Audit WordPress upload directories for any suspicious or unexpected PHP files and remove them
• Review web server logs for evidence of exploitation attempts targeting the vulnerable endpoint

Patch Information

Organizations should check the CodeCanyon Product Page for the latest version of WooCommerce Designer Pro that addresses this vulnerability. Additionally, the Wordfence Vulnerability Analysis provides detailed information about the vulnerability and remediation guidance.

Workarounds

• Implement web application firewall rules to block requests to the wcdp_save_canvas_design_ajax AJAX action
• Restrict file upload functionality by adding server-level validation for allowed file types
• Configure the web server to prevent PHP execution in upload directories using .htaccess rules or server configuration
• Temporarily disable AJAX functionality for the WooCommerce Designer Pro plugin if business operations permit

# Example: Disable PHP execution in WordPress uploads directory (Apache)
# Add to .htaccess in wp-content/uploads/

<Files *.php>
    deny from all
</Files>

# Example: Block vulnerable endpoint at web server level (Nginx)
location ~ /wp-admin/admin-ajax\.php {
    if ($arg_action = "wcdp_save_canvas_design_ajax") {
        return 403;
    }
}