Overview
CVE-2025-47944 is a serious vulnerability in Multer, a middleware for Node.js, used in handling `multipart/form-data`. It affects versions 1.4.4-lts.1 and earlier, causing potential system compromise or data leakage. This vulnerability is significant due to its potential impact on system availability, should an attacker exploit it to trigger a Denial of Service (DoS) attack.
Vulnerability Summary
CVE ID: CVE-2025-47944
Severity: High (7.5 CVSS Score)
Attack Vector: Remote
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
Product | Affected Versions
Multer Middleware for Node.js | 1.4.4-lts.1 and prior
How the Exploit Works
The vulnerability exists due to the way Multer processes malformed multi-part upload requests. An attacker can send a specially crafted multi-part upload request that triggers an unhandled exception in Multer, leading to a crash of the process. This results in a DoS situation, disrupting the availability of the service.
Conceptual Example Code
An attacker could potentially exploit this vulnerability by sending a malformed multi-part upload request as shown in the conceptual example below:
POST /upload/endpoint HTTP/1.1
Host: target.example.com
Content-Type: multipart/form-data; boundary=badboundary
--badboundary
Content-Disposition: form-data; name="file"; filename="malicious_file"
Content-Type: application/octet-stream
{ "malicious_payload": "..." }
--badboundary--
In this hypothetical example, the `boundary` parameter within the `Content-Type` header is malformed, which could cause Multer to throw an unhandled exception and crash the process.
