Bug 2477204 (CVE-2026-44000)

Summary:	CVE-2026-44000 vm2: vm2: Sandbox escape allows direct interaction with host objects
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 (before 3.11.0). Host-side Promises that resolve to host objects deliver values to sandbox .then() callbacks without cross-realm conversion (ensureThis() instead of from()/proxy wrapping), allowing sandbox code to interact with host objects directly. Fixed in 3.11.0.	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 2026-05-13 18:02:28 UTC

vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.0, a sandbox boundary violation in vm2 allows host object identity to cross into the sandbox through host Promise resolution. When a host-side Promise that resolves to a host object is exposed to the sandbox, the value delivered to the sandbox .then() callback preserves host identity. This allows the sandbox to interact with the host object directly, including performing identity checks using host-side WeakMap and mutating host object state from inside the sandbox. This behavior occurs because the Promise fulfillment wrapper uses ensureThis() instead of the stronger cross-realm conversion path (from() / proxy wrapping). If no prototype mapping is found, ensureThis() returns the original object. As a result, objects resolved by host Promises can cross the sandbox boundary without proper isolation. This vulnerability is fixed in 3.11.0.