piscina is a node.js worker pool implementation. Prior to 6.0.0-rc.2, 5.2.0, and 4.9.3, piscina's constructor and run() paths read the filename option via plain member access. Both reads fall through the prototype chain when the caller's options object doesn't have filename as an own property. When Object.prototype.filename is polluted upstream the inherited value flows to worker_threads.Worker import and the attacker's .mjs runs in the worker. This vulnerability is fixed in 6.0.0-rc.2, 5.2.0, and 4.9.3.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-x9g3-xrwr-cwfg piscina: Prototype Pollution Gadget → RCE via inherited options.filename
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 26 Jun 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-915
References
Metrics threat_severity

None

threat_severity

Important


Wed, 24 Jun 2026 12:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Tue, 23 Jun 2026 21:30:00 +0000

Type Values Removed Values Added
First Time appeared Piscinajs
Piscinajs piscina
Vendors & Products Piscinajs
Piscinajs piscina

Mon, 22 Jun 2026 17:30:00 +0000

Type Values Removed Values Added
Description piscina is a node.js worker pool implementation. Prior to 6.0.0-rc.2, 5.2.0, and 4.9.3, piscina's constructor and run() paths read the filename option via plain member access. Both reads fall through the prototype chain when the caller's options object doesn't have filename as an own property. When Object.prototype.filename is polluted upstream the inherited value flows to worker_threads.Worker import and the attacker's .mjs runs in the worker. This vulnerability is fixed in 6.0.0-rc.2, 5.2.0, and 4.9.3.
Title piscina: Prototype Pollution Gadget → RCE via inherited options.filename
Weaknesses CWE-1321
CWE-94
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-23T15:51:04.171Z

Reserved: 2026-06-16T18:57:40.183Z

Link: CVE-2026-55388

cve-icon Vulnrichment

Updated: 2026-06-23T15:49:54.520Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Important

Publid Date: 2026-06-22T16:50:40Z

Links: CVE-2026-55388 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-06-26T04:15:11Z

Weaknesses