NodeVM builtin denylist bypass via process and inspector/promises allows host code executionGHSA-rp36-8xq3-r6c4
CRITICALFix: patriksimek/vm2@a1ed47aGHSA-rp36-8xq3-r6c4 is a critical-severity (CVSS 10) CWE-693 vulnerability in vm2. A fix is available for vm2 — see the affected versions and patch details below.
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-rp36-8xq3-r6c4.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
vm2npmDescription
Summary
NodeVM blocks several dangerous Node.js builtins such as module, worker_threads, cluster, vm, repl, and inspector.
However, the denylist misses process and inspector/promises. Both can be used from sandboxed code to reach host-side execution primitives.
This allows sandboxed code to bypass the intended builtin restrictions and execute code in the host process.
Details
The dangerous builtin denylist is defined in lib/builtin.js. This list does not include:
process
inspector/promises
Non-denied builtins are exposed to the sandbox through:
builtins.set(key, special ? special : vm => vm.readonly(hostRequire(key)));
Because of this, sandboxed code can bypass the expected restrictions in two ways:
require('process').getBuiltinModule('child_process')reloadschild_process, even whenchild_processis excluded.require('inspector/promises')exposes the Inspector protocol and can callRuntime.evaluatein the host process.
PoC
Tested on:
vm2: 3.11.2
Node.js: v25.9.0
Run from the vm2 repository root:
node poc/dangerous-builtin-denylist-rce.js
dangerous-builtin-denylist-rce.js
The PoC first confirms the intended restrictions work:
require("inspector"): BLOCKED
require("child_process"): BLOCKED
Then it bypasses them:
require("process").getBuiltinModule("child_process").execFileSync(...)
This spawns a host child process. It also confirms:
require("inspector/promises").Session().post("Runtime.evaluate", ...)
This evaluates JavaScript in the host process.
<img width="858" height="766" alt="Screenshot 2026-05-10 at 11 53 33 AM" src="https://github.com/user-attachments/assets/7614aecb-5ffd-4c41-bfe8-e1fcb3b1bb59" />Impact
An attacker who can run untrusted JavaScript inside NodeVM with affected builtin settings can escape the sandbox and execute arbitrary code in the host process.
This can lead to full compromise of the application process, including reading files, writing files, spawning processes, and accessing host environment secrets.
(This is not reachable with the default NodeVM configuration where require is disabled or no affected builtins are allowed. It affects applications that allow process, inspector/promises, or the wildcard "*" in require.builtin.)
Suggested fix
Add process and inspector/promises to the dangerous builtin blocklist.
Also consider blocking dangerous builtin families by prefix, for example blocking both:
inspector
inspector/*
instead of only exact module names.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | vm2 | all versions | 3.11.4npm install vm2@3.11.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vm2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update vm2 to 3.11.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rp36-8xq3-r6c4 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
The Red Hat Product Security team has rated the impact of this vulnerability as Moderate in Red Hat Developer Hub and Ansible Automation Platform.The affected package is present in both products as a transitive dependency; however, the vulnerable sandbox functionality is not invoked in any production code path. The…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for GHSA-rp36-8xq3-r6c4 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Ansible Automation Platform 2.1 | ansible-automation-platform/automation-portal:1785854226 | RHSA-2026:50850 |
| Red Hat Developer Hub 1.10 | rhdh/rhdh-hub-rhel9:1783448184 | RHSA-2026:36754 |
| Red Hat Developer Hub 1.9 | rhdh/rhdh-hub-rhel9:1782761244 | RHSA-2026:33574 |
Frequently Asked Questions
Is GHSA-rp36-8xq3-r6c4 in your dependencies?
Find it across npm, including transitive dependencies.