Home/CVE/multiparty@4.2.3 and lower versions are vulnerable to denial of service via uncaught exception. By sending a multipart/f
CVE

CVE-2026-8161

multiparty@4.2.3 and lower versions are vulnerable to denial of service via uncaught exception. By sending a multipart/f

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.

HIGH · CVSS 7.5 EPSS 0.00016
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
CWE-248Uncaught Exception
▤

Affected Products & Versions

1
pillarjs multiparty< 4.3.0
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
npm multiparty HIGH fixed in 4.3.0
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · ce714d77-add3-4f53-aff5-83d477b104bb
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD12 May 2026 · 10:16 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

2
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://cna.openjsf.org/security-advisories.htmlThird Party Advisory
https://github.com/pillarjs/multiparty/security/advisories/GHSA-qxch-whhj-8956Vendor Advisory
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