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.

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History

Fri, 28 Aug 2026 22:00:00 +0000

Type Values Removed Values Added
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.
Title multer vulnerable to Denial of Service via crafted multipart field names
Weaknesses CWE-248
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: openjs

Published:

Updated: 2026-08-28T20:03:23.114Z

Reserved: 2026-08-20T10:53:48.073Z

Link: CVE-2026-77078

cve-icon Vulnrichment

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cve-icon NVD

Status : Received

Published: 2026-08-28T22:16:53.883

Modified: 2026-08-28T22:16:53.883

Link: CVE-2026-77078

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses