What’s Vulnerable › Vulnerabilities

CVE-2026-102992: piscina: Prototype-pollution gadget in ThreadPool.options allows RCE via execArgv / loadBalancer / env

• Severity: critical (CVSS 9.2 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-30 · updated 2026-09-30
• Weakness: CWE-1321

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.

Affected products

• piscinajs piscina: before 4.9.4; from 5.0.0, < 5.3.2; from 6.0.0-rc.1, < 6.0.0-rc.5

References

• https://github.com/piscinajs/piscina/commit/0cb12fca37f526065b072592afe954574dcc656f
• https://github.com/piscinajs/piscina/commit/2f69f67159a0e48b38fd61fa4a91c2fdc19fff72
• https://github.com/piscinajs/piscina/commit/5be7bbb19e3787bb698862cd516121a578d690f7
• https://github.com/piscinajs/piscina/commit/bebbda255c2981cecddd36b171b94be2fd41c9a6
• https://github.com/piscinajs/piscina/releases/tag/v4.9.4
• https://github.com/piscinajs/piscina/releases/tag/v5.3.2
• https://github.com/piscinajs/piscina/releases/tag/v6.0.0-rc.5
• https://github.com/piscinajs/piscina/security/advisories/GHSA-67c8-pqhq-4rmx
• https://github.com/piscinajs/piscina/security/advisories/GHSA-67c8-pqhq-4rmx

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