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Medium 6.5Published May 13, 2026

CVE-2026-44000vm2: sandbox boundary bypass via host Promise resolution preserving host object identity

Updated under an hour ago ()

Does this affect you?

It affects patriksimek vm2 and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Weakness (CWE)
CWE-693
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Analyzed
Record last updated
May 13, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
patriksimek vm2
patriksimek:vm2 (from the name)
before 3.11.0
CNA record
vm2_project vm2
vm2_project:vm2
before 3.11.0
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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