CVE-2026-47209 vm2: Bridge Proxy set trap ignores receiver parameter, enabling host object property injection via prototype chain

vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, the BaseHandler.set trap in bridge.js line 1231 ignores the receiver parameter and unconditionally writes to the host target object. Per the Proxy set trap specification, when receiver !== proxy e.g., when a child object...

CVE-2026-47209

vm2 (Node.js sandbox) had a vulnerability in the BaseHandler.set trap that ignores the receiver parameter and always writes to the host target, enabling inherited-property writes to leak onto host objects via prototype chains. This can allow attackers to assign Symbol-keyed properties (e.g., node...

vm2's Bridge Proxy set trap ignores receiver parameter, enabling host object property injection via prototype chain

Summary The BaseHandler.set trap in bridge.js line 1231 ignores the receiver parameter and unconditionally writes to the host target object. Per the Proxy set trap specification, when receiver !== proxy e.g., when a child object inherits from the proxy via Object.create, the property assignment...

Arbitrary Code Injection

Overview vm2 is a sandbox that can run untrusted code with whitelisted Node's built-in modules. Affected versions of this package are vulnerable to Arbitrary Code Injection through the BaseHandler write traps in lib/bridge.js. An attacker can mutate host Object.prototype, Array.prototype,...

GHSA-VWRP-X96C-MHWQ vm2: Mutable Proxies for Host Intrinsic Prototypes Allows Sandbox Escape

Summary vm2's bridge exposes mutable proxies for real host-realm intrinsic prototypes and then forwards sandbox writes into the underlying host objects with otherReflectSet and otherReflectDefineProperty, which lets attacker-controlled JavaScript running in a default VM or inherited NodeVM mutate...