# CVE-2025-48997: Multer Denial of Service via unhandled exception

Source: https://junglewise.ai/threats/cve-2025-48997-multer-denial-of-service-via-unhandled-exception  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-06-05. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2025-48997 · Severity: medium · CVSS 4 · Published 2025-06-05

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.

Technologies: [multer (npm)](https://junglewise.ai/threats/technologies/npm-multer). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2025-48997 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-48997 being exploited in the wild.

**How severe is CVE-2025-48997?** Medium severity, with a CVSS score of 4, published 5 June 2025.

**Which products and versions are affected?** multer (npm) SEMVER:introduced=1.4.4-lts.1,fixed=2.0.1.

**Is there a fix for CVE-2025-48997?** Yes. multer (npm): upgrade to 2.0.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2025-48997 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2025-48997?** Check whether you run multer (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- multer (npm): upgrade to 2.0.1 or later

  ```sh
  npm install multer@2.0.1
  ```


## 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

## Identifiers

- CVE-2025-48997
- GHSA-g5hg-p3ph-g8qg

## 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

## References

- [https://github.com/expressjs/multer/security/advisories/GHSA-g5hg-p3ph-g8qg](https://github.com/expressjs/multer/security/advisories/GHSA-g5hg-p3ph-g8qg)

## Related threats

- [multer denial of service in asynchronous fileFilter after request teardown](https://junglewise.ai/threats/cve-2026-113872-multer-is-a-middleware-for-node-js-that-handles-multipart-form)
- [Express multer Denial of Service via orphaned disk writes](https://junglewise.ai/threats/cve-2026-88932-express-multer-denial-of-service-via-orphaned-disk-writes)
- [multer denial of service via oversized array index](https://junglewise.ai/threats/cve-2026-82333-multer-denial-of-service-via-oversized-array-index-in-field-names)
- [multer Denial of Service via crafted multipart field names](https://junglewise.ai/threats/cve-2026-77078-multer-denial-of-service-via-crafted-multipart-field-names)
- [multer file size limit bypass via async fileFilter race condition](https://junglewise.ai/threats/cve-2026-77063-multer-file-size-limit-bypass-via-async-filefilter-race-condition)