CVE-2026-55388
High
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.
SeverityHigh
CVSS8.1
Exploit probability—
ProductPiscina
PublishedJun 22, 2026
First seenJun 22, 2026
Weakness typeCWE-94Code injectionCWE-1321Prototype pollution
How to fix
Update
- piscina5.2.0, 4.9.3, 6.0.0-rc.2 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| piscinanpm | 5.0.0-alpha.0 ≤ v < 5.2.0, v < 4.9.3, 6.0.0-rc.1 ≤ v < 6.0.0-rc.2 | 5.2.0, 4.9.3, 6.0.0-rc.2 |
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