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[ CVE-2026-102992 · Published 30 Sep 2026 ]

piscina: Prototype-pollution gadget in ThreadPool.options allows RCE via execArgv / loadBalancer / env

CVSS 9.2 EPSS <1%Fix available

[ Why it matters ]Priority signals

  • Public proof-of-concept exploit exists (CISA SSVC)
  • Critical severity: CVSS 9.2

[ Description ]Official description

piscina is a node.js worker pool implementation. Prior to 4.9.4, 5.3.2, and 6.0.0-rc.5, Piscina stores ThreadPool.options in src/index.ts as a plain object that inherits from Object.prototype. Applications with a separate prototype-pollution primitive can therefore supply inherited values for security-sensitive options that do not have own defaults. An inherited execArgv value is passed to the Node.js Worker constructor and can preload attacker-controlled code in worker threads, an inherited loadBalancer function can execute during task scheduling, and inherited env values can alter worker environments. This issue is fixed in versions 4.9.4, 5.3.2, and 6.0.0-rc.5.

[ Fixes ]Fixes and patches

  • piscina 5.3.2Fixed version · GitHub Advisories · npm package piscina: upgrade to 5.3.2 or later (affected >= 5.0.0, < 5.3.2)
  • piscina 4.9.4Fixed version · GitHub Advisories · npm package piscina: upgrade to 4.9.4 or later (affected < 4.9.4)
  • piscina 6.0.0-rc.5Fixed version · GitHub Advisories · npm package piscina: upgrade to 6.0.0-rc.5 or later (affected >= 6.0.0-rc.1, < 6.0.0-rc.5)

[ Packages ]Affected open-source packages

[ References ]References