CVE-2026-8161

multiparty vulnerable to Denial of Service via Prototype Pollution leading to Uncaught Exception

Published May 12, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Github GHSA Github GHSA GHSA-qxch-whhj-8956 multiparty: Denial of Service via Prototype Pollution leads to Uncaught Exception
History
Type Values Removed Values Added
First Time appeared Pillarjs
Pillarjs multiparty
CPEs cpe:2.3:a:pillarjs:multiparty:*:*:*:*:*:node.js:*:*
Vendors & Products Pillarjs
Pillarjs multiparty
Type Values Removed Values Added
First Time appeared Multiparty
Multiparty multiparty
Vendors & Products Multiparty
Multiparty multiparty
Type Values Removed Values Added
Metrics ssvc

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

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
openjs
Published
Updated
May 12, 2026, 12:32 PM
Reserved
May 8, 2026, 10:38 AM
Status
Analyzed
Published
May 12, 2026, 10:16 AM
Modified
Nov 11, 2026, 8:10 PM