CVE-2026-47209

The record

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.

Affected packages

Related vulnerabilities

• GHSA-c4cf-2hgv-2qv6 vm2's Bridge Proxy set trap ignores receiver parameter, enabling host object property… Same vulnerability
• CVE-2026-47210 vm2 is an open source vm/sandbox for Node.js. Also affects vm2
• CVE-2026-47139 vm2 is an open source vm/sandbox for Node.js. Also affects vm2
• CVE-2026-47208 vm2 is an open source vm/sandbox for Node.js. Also affects vm2
• CVE-2026-47135 vm2 is an open source vm/sandbox for Node.js. Also affects vm2
• CVE-2026-47137 vm2 is an open source vm/sandbox for Node.js. Also affects vm2
• CVE-2026-47141 vm2 is an open source vm/sandbox for Node.js. Also affects vm2
• CVE-2026-47140 vm2 is an open source vm/sandbox for Node.js. Also affects vm2