multiparty vulnerable to Denial of Service via Prototype Pollution leading to Uncaught Exception
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-248.
Summary
[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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| multiparty | multiparty | up to 4.2.3 | 4.3.0 | Patch available | CNA |
| — | multiparty (npm) | before 4.3.0 | 4.3.0 | Patch available | GHSA-qxch-whhj-8956 |
- multiparty Vendormultiparty Affected up to 4.2.3 Fixed in 4.3.0 Patch available CNA
- multiparty (npm) Vendor— Affected before 4.3.0 Fixed in 4.3.0 Patch available GHSA-qxch-whhj-8956
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:pillarjs:multiparty:*:*:*:*:*:node.js:*:* | before 4.3.0 | Vulnerable | multiparty |
- cpe:2.3:a:pillarjs:multiparty:*:*:*:*:*:node.js:*:* Versions before 4.3.0 Vulnerable ·multiparty
Remediation
- Fix · CNA multiparty (multiparty) Fixed in 4.3.0
- Fix · GHSA-qxch-whhj-8956 multiparty (npm) Fixed in 4.3.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-8161
- 2026-10-03 Alias added: GHSA-qxch-whhj-8956
- 2026-10-25 Priority changed: MEDIUM → LOW
References
More Multiparty vulnerabilities
- TI-2026-07187 multiparty vulnerable to Denial of Service via Uncaught Exception in filename* parameter parsing CVSS 3.1HIGH 7.5
- TI-2026-07185 multiparty vulnerable to ReDoS via filename parsing CVSS 3.1HIGH 7.5
Sources
- CVE-2026-8161 · CVE Program
- CVE-2026-8161 · NVD
- FIRST EPSS
- GHSA-qxch-whhj-8956 · GitHub Advisory Database · CC BY 4.0
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