CVE-2026-34156

CVE-2026-34156 is a critical sandbox escape vulnerability in NocoBase, an AI-powered no-code/low-code platform for building business applications and enterprise solutions. The issue affects the Workflow Script Node prior to version 2.0.28, which executes user-supplied JavaScript within a Node.js vm sandbox protected by a custom require allowlist controlled by the WORKFLOW_SCRIPT_MODULES environment variable. However, the console object injected into the sandbox context exposes host-realm WritableWorkerStdio stream objects through console._stdout and console._stderr, enabling prototype chain traversal to bypass sandbox restrictions. The vulnerability carries a CVSS v3.1 base score of 9.9 (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H) and is associated with CWE-913.

An authenticated attacker with low privileges can exploit this vulnerability remotely over the network with low complexity and no user interaction required. By crafting malicious JavaScript in a workflow script, the attacker traverses the prototype chain from the exposed console streams to access host-realm objects, escaping the sandbox and achieving remote code execution (RCE) as the root user running the NocoBase process.

The vulnerability has been patched in NocoBase version 2.0.28, as detailed in the project's security advisory (GHSA-px3p-vgh9-m57c), release notes, and associated pull request. Security practitioners should upgrade to 2.0.28 or later and review configurations of the WORKFLOW_SCRIPT_MODULES environment variable to ensure robust module restrictions.

NocoBase's AI-powered nature may amplify risks in environments leveraging its no-code workflows for automated business logic, though no public evidence of real-world exploitation has been reported.