CVE-2026-8161highCWE-1321CWE-248

CVE-2026-8161: high-severity vulnerability in multiparty

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

Published

Follow this CVE+ Monitor multiparty+ Monitor node-multiparty

E-mail alert when it lands in KEV, gets a public PoC or its score goes up.

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.5epss 0.5%
from disclosure to weaponsame day
Published on NVDMay 12
1st PoCMay 11
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
multiparty · multiparty
⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
Related CVEs — multiparty

In the same product, most dangerous first.

CVE-2026-87908HIGHmultiparty vulnerable to Denial of Service via unbounded part-header accumulationEPSS 0.5%CVE-2026-8159HIGHmultiparty vulnerable to ReDoS via filename parsingEPSS 0.3%CVE-2026-8162HIGHmultiparty vulnerable to Denial of Service via Uncaught Exception in filename* parameter parsingEPSS 0.3%