CVE-2026-82333

multer is a middleware for handling multipart/form-data in Node.js. A small multipart request with two specially crafted text field names can make multer's field parser synchronously iterate a maximum-length sparse array, blocking the event loop so the process cannot handle other requests. A large numeric array index in the first field allocates a maximum-length sparse array, and a second field with a non-numeric key then triggers a full-length iteration inside the append-field dependency. All versions before 2.3.0 are affected, and this is a remotely triggerable denial of service. multer 2.3.0 adds an opt-in fieldArrayIndexLimit option that rejects oversized array indexes. Upgrade to multer 2.3.0 and set limits.fieldArrayIndexLimit to the largest array index your application needs to remediate.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://cna.openjsf.org/security-advisories.html	Vendor Advisory
https://github.com/expressjs/multer/security/advisories/GHSA-535w-7cp7-47q4	Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:expressjs:multer:*:*:*:*:*:node.js:*:*

History

No history.

Information

Published : 2026-08-28 22:16

Updated : 2026-09-02 14:45

NVD link : CVE-2026-82333

Mitre link : CVE-2026-82333

CVE.ORG link : CVE-2026-82333

JSON object : View

Products Affected

expressjs

multer

CWE

CWE-400

Uncontrolled Resource Consumption

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