PT-2026-49233 · Multer · Multer

Tndud042713 + 1 · Published 2026-06-15 · Updated 2026-06-15 · CVE-2026-5079

NVD

CVSS v3.1

7.5

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Impact: multer versions 1.0.0 through 2.1.1 and 3.0.0-alpha.1 are vulnerable to a Denial of Service via deeply nested field names in multipart form data. The append-field dependency parses bracket notation in field names with no limit on nesting depth, allowing an attacker to force allocation of deeply nested object structures that consume CPU and memory. A single HTTP request with a crafted multipart body is sufficient to exploit this.

Patches: Users should upgrade to multer 2.2.0 (2.x line) or 3.0.0-alpha.2 (3.x prerelease) and configure the new limits.fieldNestingDepth option to the minimum depth their application requires.

Workarounds: Set limits.fields to a reasonable value to reduce the number of fields an attacker can send per request. This does not fully mitigate the issue but limits the impact.

Fix

Resource Exhaustion

Weakness Enumeration

CWE-400

Related Identifiers

CVE-2026-5079

Affected Products

Multer

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-5079 · Security Note
• https://cna.openjsf.org/security-advisories.html · Note
• https://github.com/expressjs/multer/security/advisories/GHSA-72gw-mp4g-v24j · Note