Overview
The Apache Commons FileUpload library, widely used software for handling file uploads in Java-based web applications, has been found to have a significant vulnerability (CVE-2025-48976). This vulnerability stems from insufficient limits on the allocation of resources for multipart headers, enabling a potential Denial of Service (DoS) attack. This issue is of critical concern to any system employing affected versions of Apache Commons FileUpload, as it may lead to system compromise or data leakage.
Vulnerability Summary
CVE ID: CVE-2025-48976
Severity: High (7.5 CVSS Score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and data leakage
Affected Products
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Product | Affected Versions
Apache Commons FileUpload | 1.0 to 1.5
Apache Commons FileUpload | 2.0.0-M1 to 2.0.0-M3
How the Exploit Works
The vulnerability lies in the way Apache Commons FileUpload processes multipart headers. By sending a specially crafted multipart request with an excessive amount of data in the headers, an attacker can exhaust system resources, causing the application to become unresponsive, leading to a DoS condition. This could potentially be exploited further to gain unauthorized access or extract sensitive data.
Conceptual Example Code
A conceptual example of the exploit might involve sending an HTTP POST request with an excessive amount of data in the multipart headers. An example might look like this:
POST /vulnerable/endpoint HTTP/1.1
Host: target.example.com
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="file"; filename="file.txt"
Content-Type: text/plain
[large amount of data]
------WebKitFormBoundary7MA4YWxkTrZu0gW--In the above example, the `[large amount of data]` will be replaced with an excessive amount of data, exhausting system resources and potentially leading to a DoS condition.
