CVE-2026-8161
multiparty vulnerable to Denial of Service via Prototype Pollution leading to Uncaught Exception
- Published
- May 12, 2026
- Updated
- May 12, 2026
- Assigning CNA
- openjs
- Evidence observed
- Aug 25, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HLow · next 30 days
- Percentile
- 40.0%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
[email protected] 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 [email protected] or higher.
Sources
1Proof-of-concept exploit for CVE-2026-8161, a denial-of-service vulnerability in multiparty multipart parser, demonstrating prototype pollution leading to uncaught exception and crash.
Responsible use
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