---
title: "CVE-2026-34156: NocoBase Affected by Sandbox Escape to RCE via console._stdout Prototype Chain Traversal in Workflow Script Node"
url: https://erroneo.us/security/cve/CVE-2026-34156/
description: "CVE-2026-34156 (@nocobase/plugin-workflow-javascript (npm)): NocoBase is an AI-powered no-code/low-code platform for building business applications and…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-31
date_modified: 2026-04-02
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-34156"
kev: false
cvss: 10
epss: 0.06793
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-34156: NocoBase Affected by Sandbox Escape to RCE via console._stdout Prototype Chain Traversal in Workflow Script Node

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (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 6.8% , percentile 94: FIRST’s model estimates a 6.8% chance of exploitation activity in the next 30 days, higher than 94% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes @nocobase/plugin-workflow-javascript (npm) <= 2.0.27, fixed in 2.0.28 . Check your lockfile, including transitive dependencies.

## What it is

NocoBase is an AI-powered no-code/low-code platform for building business applications and enterprise solutions. Prior to version 2.0.28, NocoBase's Workflow Script Node executes user-supplied JavaScript inside a Node.js vm sandbox with a custom require allowlist (controlled by WORKFLOWSCRIPTMODULES env var). However, the console object passed into the sandbox context exposes host-realm WritableWorkerStdio stream objects via console.stdout and console.stderr. An authenticated attacker can traverse the prototype chain to escape the sandbox and achieve Remote Code Execution as root. This issue has been patched in version 2.0.28.

## Affected packages

- npm `@nocobase/plugin-workflow-javascript` <= 2.0.27 → fixed: 2.0.28

## Affected products (CVE record)

- nocobase nocobase: < 2.0.28

## Severity

- GitHub_M CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.9 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 6.79% probability of exploitation activity in the next 30 days; percentile 94.

## Sources

- [GitHub Advisory GHSA-px3p-vgh9-m57c](https://github.com/advisories/GHSA-px3p-vgh9-m57c)
- [CVE.org record CVE-2026-34156](https://www.cve.org/CVERecord?id=CVE-2026-34156)
- [NVD entry CVE-2026-34156](https://nvd.nist.gov/vuln/detail/CVE-2026-34156)
- [github.com](https://github.com/nocobase/nocobase/security/advisories/GHSA-px3p-vgh9-m57c)
- [github.com](https://github.com/nocobase/nocobase/pull/8967)
- [github.com](https://github.com/nocobase/nocobase/releases/tag/v2.0.28)

---
Source page: https://erroneo.us/security/cve/CVE-2026-34156/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt