CVE-2026-8161: Pillarjs Multiparty

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• Pillarjs Multiparty: before 4.3.0 (fixed in 4.3.0)

Published 2026-05-12. Last modified 2026-06-17.