Cyber Resilience

CVE-2026-8161

Pillarjs Multiparty ≤ 4.3.0

Published
12 May 2026
Modified
17 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0047 39th percentile
Risk Priority 58 floored blend · peak EPSS

Summary

CVE-2026-8161 is a high-severity Uncaught Exception (CWE-248) vulnerability in Pillarjs Multiparty. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 39th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-8 (Security and Privacy Engineering Principles) and SC-24 (Fail in Known State) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-248CWE-1321

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1565 Data Manipulation Impact
Adversaries may insert, delete, or manipulate data in order to influence external outcomes or hide activity, thus threatening the integrity of the data.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-8162Same product: Pillarjs Multiparty
CVE-2026-8159Same product: Pillarjs Multiparty
CVE-2026-73088Shared CWE-1321, CWE-248
CVE-2026-4923Same vendor: Pillarjs
CVE-2026-4867Same vendor: Pillarjs
CVE-2026-4926Same vendor: Pillarjs
CVE-2024-36578Shared CWE-1321
CVE-2026-34621Shared CWE-1321
CVE-2025-3193Shared CWE-1321
CVE-2024-30564Shared CWE-1321

Affected Assets

pillarjs
multiparty
≤ 4.3.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V15.3.6

Mitigating Controls (NIST 800-53 r5) AI

SA-8 Security and Privacy Engineering Principles partial match

Security engineering principles include robust exception management to keep the system in a defined state.

SC-24 Fail in Known State partial match

Fail-in-known-state reduces the impact when an uncaught exception occurs by preserving a safe condition.

SI-11 Error Handling partial match

Error handling requirements force structured catching and response to exceptions instead of allowing them to propagate uncaught.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices explicitly require structured exception handling to prevent uncaught exceptions from reaching production.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect uncaught exceptions before production deployment.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle includes exception-handling standards that reduce uncaught exceptions.

A.8.26 Application security requirements partial match
prevents

Application security requirements typically mandate robust error and exception handling.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles call for centralized, comprehensive exception management.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly require catching and handling exceptions to prevent crashes or leaks.

A.8.32 Change management partial match
prevents

Change-management processes ensure security fixes for prototype-pollution issues are tracked and deployed.

References