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Vulnerability · Published Oct 2, 2026 · Assigned by GitHub_M

CVE-2026-104848Tinypool: Prototype Pollution gadget in worker options leads to Remote Code Execution

Critical 9.5

In plain English

A critical-severity prototype pollution in tinypool from tinylibs. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)9.5Critical
Exploit odds (30 days)0.5%top 57.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

Tinypool is a minimal Node.js worker thread pool implementation. Prior to 2.1.1, Tinypool constructs ThreadPool.options from a normal options object and reads the execArgv and env worker options in dist/index.js, allowing values inherited from a polluted Object.prototype to be copied into own properties and passed to worker_threads.Worker. An attacker who can first pollute either property can cause each newly spawned worker to load attacker-selected JavaScript through command-line preload arguments or NODE_OPTIONS, resulting in code execution with the host process's privileges and possible access to CI secrets, signing material, or build artifacts. This issue is fixed in version 2.1.1.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
npmtinypool2.1.1GHSA-5gmw-xhrv-c9v3

Affected products (as reported)

VendorProductVersions
tinylibs tinypool < 2.1.1

Weakness: CWE-1321 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

References