Quick answers
- Is CVE-2026-8161 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-8161 being exploited in the wild.
- How severe is CVE-2026-8161?
- High severity, with a CVSS score of 7.5, published 12 May 2026.
- Which products and versions are affected?
- multiparty (npm) SEMVER:introduced=0,fixed=4.3.0; Pillarjs Multiparty <= 4.2.3, <=4.2.3.
- Is there a fix for CVE-2026-8161?
- Yes. multiparty (npm): upgrade to 4.3.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-8161 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-8161?
- Check whether you run multiparty (npm) or Pillarjs Multiparty at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- multiparty (npm): upgrade to 4.3.0 or later
npm install multiparty@4.3.0
Technical details
The multiparty library (versions 4.2.3 and lower) is vulnerable to a denial-of-service (DoS) attack caused by an uncaught exception. The vulnerability occurs when a 'multipart/form-data' request contains a field name that matches an inherited property of 'Object.prototype' (such as '__proto__', 'constructor', or 'toString'). When the parser attempts to handle these fields, it incorrectly invokes the '.push()' method on the inherited prototype value instead of an array. This results in a 'TypeError' that propagates as an uncaught exception, crashing the Node.js process. The issue is fixed in version 4.3.0.
Affected products
- pillarjs multiparty <= 4.2.3
Identifiers
- CVE-2026-8161
- GHSA-qxch-whhj-8956
Timeline
- 2026-05-12: disclosed: Vulnerability published to NVD
- 2026-05-18: advisory: GitHub Advisory published