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.

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Source ID Title
Github GHSA Github GHSA GHSA-c4cf-2hgv-2qv6 vm2's Bridge Proxy set trap ignores receiver parameter, enabling host object property injection via prototype chain
Fixes

Solution

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Workaround

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History

Fri, 12 Jun 2026 15:45:00 +0000

Type Values Removed Values Added
First Time appeared Patriksimek
Patriksimek vm2
Vendors & Products Patriksimek
Patriksimek vm2

Fri, 12 Jun 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 12 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
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.
Title vm2: Bridge Proxy set trap ignores receiver parameter, enabling host object property injection via prototype chain
Weaknesses CWE-693
References
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-12T15:03:57.071Z

Reserved: 2026-05-18T22:25:21.257Z

Link: CVE-2026-47209

cve-icon Vulnrichment

Updated: 2026-06-12T15:03:50.873Z

cve-icon NVD

Status : Deferred

Published: 2026-06-12T15:16:28.900

Modified: 2026-06-12T16:03:15.620

Link: CVE-2026-47209

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-12T16:30:14Z

Weaknesses