Executive brief
Multer is a popular Node.js middleware for handling file uploads in web applications. A vulnerability allows attackers to crash the application process by sending a specially crafted file upload request with an empty field name. This can cause service disruptions and impact application availability.
Technical details
The vulnerability is a CWE-248 uncaught exception flaw in Multer versions >=1.4.4-lts.1 and <2.0.1. When an attacker sends an upload file request with an empty string field name, the application fails to properly handle the exception, causing an unhandled exception that crashes the process. The attack requires only network connectivity and no authentication or user interaction. An attacker can repeatedly send such requests to achieve a denial of service condition. The vulnerability has been patched in version 2.0.1.
Affected products
- Express.js Multer >=1.4.4-lts.1, <2.0.1
Timeline
- 2025-06-03: disclosed: CVE-2025-48997 assigned
- 2025-06-05: disclosed: GHSA-g5hg-p3ph-g8qg advisory published
- 2025-06-05: patched: Patch released in version 2.0.1