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
HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 96% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, nvd
7.5
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 4.1%
- KEV
- Not listed
Published
May 12, 2026
Last Modified
May 13, 2026
References (2)
- ce714d77-add3-4f53-aff5-83d477b104bbhttps://cna.openjsf.org/security-advisories.html
- ce714d77-add3-4f53-aff5-83d477b104bbhttps://github.com/pillarjs/multiparty/security/advisories/GHSA-qxch-whhj-8956
Frequently asked(5)
What is CVE-2026-8161?
CVE-2026-8161 is a high vulnerability published on May 12, 2026. 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…
When was CVE-2026-8161 disclosed?
CVE-2026-8161 was first published in the National Vulnerability Database on May 12, 2026, with the most recent update on May 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8161 actively exploited?
CVE-2026-8161 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-8161?
CVE-2026-8161 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-8161?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8161, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-8161
Is Your Infrastructure Affected by CVE-2026-8161?
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