piscina: Prototype-pollution gadget in ThreadPool.options allows RCE via execArgv / loadBalancer / env
At a glance
Severity
CRITICAL 9.2
EPSS
EPSS 0.51 % · percentile 43 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
GitHub_M
NVD status
Deferred
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.
