multiparty@4.2.3 and lower versions are vulnerable to denial of service via uncaught exception. By sending a multipart/form-data request with a field name that collides with an inherited Object.prototype property such as __proto__, constructor, or toString, the parser invokes .push() on the inherited prototype value rather than an array, throwing a TypeError that propagates as an uncaught exception and crashes the process. Impact: any service accepting multipart uploads via multiparty is affected. Workarounds: none. Upgrade to multiparty@4.3.0 or higher.

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Fixes

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History

Tue, 12 May 2026 13:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 12 May 2026 09:30:00 +0000

Type Values Removed Values Added
Description multiparty@4.2.3 and lower versions are vulnerable to denial of service via uncaught exception. By sending a multipart/form-data request with a field name that collides with an inherited Object.prototype property such as __proto__, constructor, or toString, the parser invokes .push() on the inherited prototype value rather than an array, throwing a TypeError that propagates as an uncaught exception and crashes the process. Impact: any service accepting multipart uploads via multiparty is affected. Workarounds: none. Upgrade to multiparty@4.3.0 or higher.
Title multiparty vulnerable to Denial of Service via Prototype Pollution leading to Uncaught Exception
Weaknesses CWE-1321
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'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: openjs

Published:

Updated: 2026-05-12T12:32:10.127Z

Reserved: 2026-05-08T10:38:20.438Z

Link: CVE-2026-8161

cve-icon Vulnrichment

Updated: 2026-05-12T12:32:04.313Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-12T10:16:48.987

Modified: 2026-05-12T15:08:22.857

Link: CVE-2026-8161

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-12T12:15:15Z

Weaknesses