Overview
The cybersecurity world is waking up to a new threat, CVE-2025-3515, a file upload vulnerability found in the popular WordPress plugin, Drag and Drop Multiple File Upload for Contact Form 7. The severity of this vulnerability stems from its potential to allow unauthenticated attackers to upload arbitrary files, including .phar or other dangerous file types, on the affected site’s server. This vulnerability could lead to potential system compromise or data leakage, as these maliciously uploaded files could be used for remote code execution on servers configured to handle .phar files as executable PHP scripts.
Vulnerability Summary
CVE ID: CVE-2025-3515
Severity: Critical (8.1 CVSS score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise, potential data leakage
Affected Products
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Product | Affected Versions
Drag and Drop Multiple File Upload for Contact Form 7 | All versions up to 1.3.8.9
How the Exploit Works
The exploit takes advantage of insufficient file type validation in the Drag and Drop Multiple File Upload for Contact Form 7 plugin. Specifically, the plugin’s blacklist can be bypassed, allowing an attacker to upload arbitrary, potentially harmful files. Most notably, malicious .phar files can be uploaded and subsequently executed as PHP scripts on servers configured to handle .phar files as such. This is particularly concerning in default Apache+mod_php configurations, where the file extension is not strictly validated before being passed to the PHP interpreter.
Conceptual Example Code
The following is a conceptual example of an HTTP POST request that could be used to exploit this vulnerability:
POST /wp-content/plugins/drag-and-drop-multiple-file-upload-contact-form-7/upload.php HTTP/1.1
Host: target.example.com
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary123456789
------WebKitFormBoundary123456789
Content-Disposition: form-data; name="file"; filename="malicious.phar"
Content-Type: application/octet-stream
[...] // Contents of the malicious .phar file here
------WebKitFormBoundary123456789--This request attempts to upload a .phar file named “malicious.phar” to the upload endpoint of the vulnerable plugin. If successful, the uploaded file could be executed as a PHP script on the server, potentially leading to remote code execution, system compromise, or data leakage.
Recommended Mitigation
The best course of action is to update the Drag and Drop Multiple File Upload for Contact Form 7 plugin to a version where this vulnerability has been patched. If a patch is not yet available, using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can provide temporary mitigation.