CVE-2026-44000

vm2: sandbox boundary bypass via host Promise resolution preserving host object identity

Published May 13, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-mpf8-4hx2-7cjg vm2 Host Promise Resolution Preserves Object Identity Across Sandbox Boundary
History
Type Values Removed Values Added
First Time appeared Vm2 Project
Vm2 Project vm2
CPEs cpe:2.3:a:vm2_project:vm2:*:*:*:*:*:node.js:*:*
Vendors & Products Vm2 Project
Vm2 Project vm2
Type Values Removed Values Added
First Time appeared Patriksimek
Patriksimek vm2
Vendors & Products Patriksimek
Patriksimek vm2
Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
Description 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.
Title vm2: sandbox boundary bypass via host Promise resolution preserving host object identity
Weaknesses CWE-693
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 13, 2026, 6:20 PM
Reserved
May 4, 2026, 8:24 PM
Status
Analyzed
Published
May 13, 2026, 6:16 PM
Modified
Oct 26, 2026, 5:10 PM