CVE-2026-47209
HighCVSS 8.6Exploitation Probability (EPSS)
Low risk16th percentile - higher than 16% of all known CVEs
Summary
In versions prior to 3.11.4, the vm2 library has a vulnerability in the BaseHandler.set method that ignores the receiver parameter and incorrectly writes to the target object. This leads to inherited properties leaking to the host object, creating an attack vector for dangerous cross-realm Symbol keys.
Risk Assessment
Organizations may be exposed to attacks that exploit this vulnerability to write unauthorized dangerous Symbol keys to host objects, potentially leading to serious security breaches.
Recommendation
It is recommended to update the vm2 library to version 3.11.4 or later to mitigate this vulnerability and secure applications against potential attacks.
Original NVD description (English source)
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.