# CVE-2026-77078: node-multer: multer is a middleware for handling multipart/form-data in Node.js

CVE-2026-77078 is fixed in node-multer on 1 platform by DEBIAN-CVE-2026-77078 (version 2.4.0+~cs3.2.0-1), released August 28, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-77078
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0049
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 28, 2026

## Description

multer is a middleware for handling multipart/form-data in Node.js. A small multipart request containing two specially crafted text field names can cause an uncaught RangeError (Invalid array length) that terminates the Node.js process. The first field uses a very large numeric array index to allocate a maximum-length sparse array, and a second field then pushes past that length, which throws inside the append-field dependency and is not caught by multer. All versions before 2.3.0 are affected, and the issue is a remotely triggerable denial of service. The issue is fixed in multer 2.3.0. Upgrade to multer 2.3.0 to remediate.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | node-multer Debian 14 | 2.4.0+~cs3.2.0-1 | [DEBIAN-CVE-2026-77078](https://patchblox.com/security/data/fix/linux/debian-cve-2026-77078.md) | Aug 28, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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