---
title: "CVE-2026-104848: Tinypool: Prototype Pollution gadget in worker options leads to Remote Code Execution"
url: https://erroneo.us/security/cve/CVE-2026-104848/
description: "CVE-2026-104848 (tinypool (npm)): Tinypool is a minimal Node.js worker thread pool implementation. Prior to 2.1.1, Tinypool constructs ThreadPool.options…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-10-02
date_modified: 2026-10-05
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-104848"
kev: false
cvss: 9.5
epss: 0.00497
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.5% , percentile 42: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 42% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes tinypool (npm) <= 2.1.0, fixed in 2.1.1 . Check your lockfile, including transitive dependencies.

## What it is

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 workerthreads.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 NODEOPTIONS, 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

- npm `tinypool` <= 2.1.0 → fixed: 2.1.1

## Affected products (CVE record)

- tinylibs tinypool: < 2.1.1

## Severity

- GitHub_M CVSS 4.0: 9.5 `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`
- GitHub CVSS 4.0: 9.5 `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`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.50% probability of exploitation activity in the next 30 days; percentile 42.

## Sources

- [GitHub Advisory GHSA-5gmw-xhrv-c9v3](https://github.com/advisories/GHSA-5gmw-xhrv-c9v3)
- [CVE.org record CVE-2026-104848](https://www.cve.org/CVERecord?id=CVE-2026-104848)
- [NVD entry CVE-2026-104848](https://nvd.nist.gov/vuln/detail/CVE-2026-104848)
- [github.com](https://github.com/tinylibs/tinypool/security/advisories/GHSA-5gmw-xhrv-c9v3)
- [github.com](https://github.com/tinylibs/tinypool/pull/134)
- [github.com](https://github.com/tinylibs/tinypool/commit/24df4e730e7d0857a6d226c9b58f8924227404fd)
- [github.com](https://github.com/tinylibs/tinypool/releases/tag/v2.1.1)

---
Source page: https://erroneo.us/security/cve/CVE-2026-104848/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt