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Mallory
CriticalPublic exploit

Sandbox escape in vm2 via Buffer prototype/property lookup abuse

IdentifiersCVE-2026-47131CWE-94

CVE-2026-47131 is a sandbox escape vulnerability in the vm2 Node.js sandbox library affecting versions prior to 3.11.4. The issue arises from abuse of prototype/property lookup behavior against native Buffer objects by combining Buffer.call.call({}.lookupGetter, Buffer, "proto"), Buffer.call.call({}.lookupSetter, Buffer, "proto"), and Node.js's ERR_INVALID_ARG_TYPE error path. This sequence allows attacker-controlled code running inside the vm2 sandbox to obtain the host environment's TypeError constructor. Access to the host constructor breaks the sandbox boundary and enables execution of arbitrary code outside the intended isolation context.

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ANALYST BRIEF

Impact, mitigation & remediation

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Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation results in complete sandbox escape from vm2 and arbitrary code execution in the host Node.js process context. An attacker can execute code outside the sandbox boundary and potentially access sensitive application data, local files, credentials, tokens, processes, and other resources available to the hosting application.

Mitigation

If you can’t patch tonight, do this now.

No effective configuration-based workaround is identified in the provided content when untrusted scripts are permitted to run inside vm2. If immediate upgrade is not possible, the only partial risk reduction is to stop executing untrusted JavaScript in affected vm2 deployments until the library can be updated.

Remediation

Patch, then assume compromise.

Upgrade vm2 to version 3.11.4 or later, which patches this issue. The provided content identifies 3.11.4 as the fixed release for CVE-2026-47131.
PUBLIC EXPLOITS

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VALID 0 / 0 TOTALView more in app

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Threat actor evidence

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Detection signatures

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Vendor-by-vendor mapping

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Social activity2

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