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.

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
piscinajs piscina affected
Version Status Constraints
< 4.9.3 affected —
>= 5.0.0-alpha.0, < 5.2.0 affected —
>= 6.0.0-rc.1, < 6.0.0-rc.2 affected —

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Project Subscriptions

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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.

References
Link Providers
https://github.com/piscinajs/piscina/security/advisories/GHSA-x9g3-xrwr-cwfg cve-icon
History

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: 2026-06-22T16:50:40.867Z

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

Link: CVE-2026-55388

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-22T19:15:04Z

Weaknesses