CVE-2026-8161multiparty vulnerable to Denial of Service via Prototype Pollution leading to Uncaught Exception
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No exploitation reported and no EPSS estimate yet.
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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
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-248, CWE-1321
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- openjs
- NVD analysis
- Analyzed
- Record last updated
- May 12, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
multiparty multiparty multiparty:multiparty (from the name) | through 4.2.3; 4.3.0 not affected | CNA record |
pillarjs multiparty pillarjs:multiparty | before 4.3.0 | NVD |
References
- https://github.com/pillarjs/multiparty/security/advisories/GHSA-qxch-whhj-8956vendor-advisory
- https://cna.openjsf.org/security-advisories.htmlthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.