CVE-2026-8161

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

HIGH
7.5
CVSS Score
Published: May 12, 2026 at 08:50 AM UTC
Updated: June 17, 2026 at 11:03 AM UTC
2 products affected across 2 vendorsMultipartyMultiparty

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Severity
HIGH7.5
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

Description

[email protected] 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 [email protected] or higher.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.3.0
v ≤ 4.2.3
Vendor states this is fixed in 4.3.0 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHopenjs
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-248CWE-1321

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