Arbitrary code execution via prototype pollution of filename option

Summary

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. A flaw was found in piscina, a Node.js worker pool implementation. This vulnerability allows an attacker to achieve arbitrary code execution by exploiting a prototype pollution issue. By manipulating the `filename` option, an attacker can cause their malicious code to be executed within the worker, potentially compromising the system's confidentiality, integrity, and availability. This is an Important flaw due to arbitrary code execution via prototype pollution. Red Hat products are not affected by this vulnerability as the vulnerable code is not present in Red Hat's `piscina` implementation. Red Hat severity: Important — CVSS 8.1 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-915. No fixing RHSA erratum has published yet; monitor the Red Hat CVE page and patch when it ships.