multer up to 2.2.x Field Parser denial of service

Summaryinfo

A vulnerability labeled as problematic has been found in multer up to 2.2.x. This impacts an unknown function of the component Field Parser. The manipulation results in denial of service. This vulnerability is identified as CVE-2026-82333. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, was found in multer up to 2.2.x. Affected is an unknown part of the component Field Parser. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-82333 since 08/28/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 2.3.0 eliminates this vulnerability.

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Productinfo

Name

• multer

Version

• 2.0
• 2.1
• 2.2

CPE 2.3info

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CPE 2.2info

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