Denial of Service Vulnerability in Multiparty by PillarJS
CVE-2026-8161

7.5HIGH

Key Information:

Vendor

Multiparty

Status
Multiparty
Vendor
CVE Published:
12 May 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-8161?

The Multiparty library, versions 4.2.3 and below, is susceptible to a denial of service attack caused by uncaught exceptions. This vulnerability arises when a multipart/form-data request is sent with a field name that collides with inherited Object.prototype properties, such as proto, constructor, or toString. The resulting action invokes .push() on the inherited property, leading to a TypeError that causes the process to crash. Any service that accepts multipart uploads using the Multiparty library is impacted. No workarounds are available; it is recommended to upgrade to version 4.3.0 or higher to mitigate this issue.

Affected Version(s)

multiparty 0 <= 4.2.3

multiparty 4.3.0

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-8161
Created by Ser0n-ath

References

https://github.com/pillarjs/multiparty/security/advisorie...
https://cna.openjsf.org/security-advisories.html

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Ser0n-ath
Sebastian Beltran
kq5y
Byambadalai Sumiya
Blake Embrey
Ulises Gascón
.