# CVE-2026-88932: Express multer Denial of Service via orphaned disk writes

Source: https://junglewise.ai/threats/cve-2026-88932-express-multer-denial-of-service-via-orphaned-disk-writes  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-14. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-88932 · Severity: medium · CVSS 5.3 · Published 2026-09-14

Multer is a widely-used Node.js middleware that handles file uploads via web forms. When uploads are aborted mid-transfer on systems using disk storage, orphaned temporary files are left behind on disk. An attacker can repeatedly initiate and abort uploads to accumulate these orphaned files, eventually exhausting available disk space and causing the application to become unavailable.

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

## Quick answers

**Is CVE-2026-88932 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-88932 being exploited in the wild.

**How severe is CVE-2026-88932?** Medium severity, with a CVSS score of 5.3, published 14 September 2026.

**Which products and versions are affected?** multer (npm) >= 2.2.0, < 2.4.0, SEMVER:introduced=2.2.0,fixed=2.4.0.

**Is there a fix for CVE-2026-88932?** Yes. multer (npm): upgrade to 2.4.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-88932 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-88932?** 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 2.4.0 or later

  ```sh
  npm install multer@2.4.0
  ```


## Technical details

The vulnerability is an incomplete fix for an earlier flaw: multer's diskStorage only cleans up in-flight uploads that have already been assigned a file path. When an upload is aborted before the storage engine assigns the path—particularly with asynchronous destination or filename functions—the uploaded file is written to disk with no removal mechanism in place, and the application cannot clean it up. An unauthenticated network attacker can exploit this by sending repeated multipart/form-data requests and aborting them to accumulate orphaned files in the upload directory or shared temporary directory until disk space is exhausted. The issue affects multer versions 2.2.0 through 2.3.0 and is resolved in version 2.4.0.

## Affected products

- Express.js multer 2.2.0 through 2.3.0

## Identifiers

- CVE-2026-88932
- GHSA-3pph-fpjx-jg34

## Timeline

- 2026-09-14: disclosed: CVE-2026-88932 published
- 2026-09-14: patched: Fixed in multer 2.4.0

## References

- [https://cna.openjsf.org/security-advisories.html](https://cna.openjsf.org/security-advisories.html)
- [https://github.com/expressjs/multer/security/advisories/GHSA-3pph-fpjx-jg34](https://github.com/expressjs/multer/security/advisories/GHSA-3pph-fpjx-jg34)

## 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)
- [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)
- [Express multer file descriptor leak on aborted uploads](https://junglewise.ai/threats/cve-2026-77037-express-multer-file-descriptor-leak-on-aborted-uploads)