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.
References9
- github.com/piscinajs/piscina/commit/0cb12fca37f526065b072592afe…
- github.com/piscinajs/piscina/commit/2f69f67159a0e48b38fd61fa4a9…
- github.com/piscinajs/piscina/commit/5be7bbb19e3787bb698862cd516…
- github.com/piscinajs/piscina/commit/bebbda255c2981cecddd36b171b…
- github.com/piscinajs/piscina/releases/tag/v4.9.4
- github.com/piscinajs/piscina/releases/tag/v5.3.2
- github.com/piscinajs/piscina/releases/tag/v6.0.0-rc.5
- github.com/piscinajs/piscina/security/advisories/GHSA-67c8-pqhq…
- github.com/piscinajs/piscina/security/advisories/GHSA-67c8-pqhq…
Metrics
- CVSS 4.0
-
9.2
CRITICAL
Score source: CNA
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 1% percentile: 44 · as of 10 November 2026
- CWE
- CWE-1321
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.