Description
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 inherits from the proxy via Object.create), the property assignment should create an own property on the receiver, not on the proxy target. The current implementation always calls otherReflectSet(object, key, value) against the host target, causing all inherited property writes to leak through to the host object. This bug provides an alternative attack vector for writing dangerous cross-realm Symbol keys (e.g., nodejs.util.promisify.custom) to host objects, bypassing any future per-trap isDangerousCrossRealmSymbol guard on the direct set path. This issue has been patched in version 3.11.4.
Problem types
CWE-693: Protection Mechanism Failure
Product status
References
github.com/...ek/vm2/security/advisories/GHSA-c4cf-2hgv-2qv6
github.com/...ommit/26d0318b5e6555be4b187ba05d6cf378ccecfe22
github.com/patriksimek/vm2/releases/tag/v3.11.4