Bug 2488397 (CVE-2026-47209)

Summary:	CVE-2026-47209 vm2: vm2: Integrity bypass via incorrect property assignment leading to potential arbitrary code execution
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	abarbaro, alizardo, dschmidt, erezende, jchui, jhe, jlanda, kshier, ktsao, nboldt, oaljalju, psrna, simaishi, smcdonal, stcannon, teagle, yguenane
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in vm2, an open-source virtual machine (VM) sandbox for Node.js. This vulnerability allows an attacker to bypass security restrictions by writing dangerous cross-realm Symbol keys to host objects. This can lead to a compromise of the integrity of the host system, potentially enabling arbitrary code execution within the Node.js environment. The issue stems from the BaseHandler.set trap in bridge.js, which incorrectly writes to the host target object even when inherited property assignments should create an own property on the receiver.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-06-12 15:02:28 UTC

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.