How severe is CVE-2026-8161?

CVE-2026-8161 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-8161 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-8161?

CVE-2026-8161 affects Pillarjs Multiparty. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-8161?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-8161 have an EU (EUVD) identifier?

Yes. CVE-2026-8161 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29440.

When was CVE-2026-8161 published?

CVE-2026-8161 was published on 2026-05-12 and last updated on 2026-06-17.

CVE-2026-8161

Q: What is CVE-2026-8161?

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.

CVE-2026-8161 is a high-severity vulnerability in Pillarjs Multiparty with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-248.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-29440
Weakness: CWE-248
Affected product: Pillarjs Multiparty
Published: 2026-05-12
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-8161?: [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.
How severe is CVE-2026-8161?: CVE-2026-8161 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-8161 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-8161?: CVE-2026-8161 affects Pillarjs Multiparty. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-8161?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-8161 have an EU (EUVD) identifier?: Yes. CVE-2026-8161 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29440.
When was CVE-2026-8161 published?: CVE-2026-8161 was published on 2026-05-12 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:pillarjs:multiparty:*:*:*:*:*:node.js:*:*

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