Skip to main content
Live Webinar with SANS (June 25)— Agentic CTI Automation for Fun & ProfitRegister Free
Mallory
CriticalPublic exploit

vm2 sandbox escape via JSPI-backed Promise.finally() species bypass

IdentifiersCVE-2026-47210CWE-913· Improper Control of…

CVE-2026-47210 is a sandbox escape vulnerability in vm2, the Node.js sandbox library, affecting versions prior to 3.11.4. When vm2 executes untrusted code with async support on runtimes that expose WebAssembly JavaScript Promise Integration (JSPI) features such as WebAssembly.promising or WebAssembly.Suspending, a JSPI-backed Promise can reach the global Promise.prototype.finally() path in a way that bypasses vm2's expected Promise-species hardening. In the described scenario, this bypass exposes a host-originated rejection object to attacker-controlled species logic, breaking the intended sandbox boundary and enabling execution of attacker-controlled code in the host process.

Share:
For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

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

Successful exploitation allows a sandbox escape from vm2 into the host Node.js process. This can result in arbitrary code execution with the privileges of the host process, including arbitrary command execution, access to local files and application data available to the process, theft of secrets, tokens, and credentials, and full compromise of applications or services that rely on vm2 for isolation.

Mitigation

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

If immediate patching is not possible, do not rely on vm2 as a security boundary for untrusted JavaScript in environments exposing WebAssembly JSPI features. Avoid or disable async execution paths that can trigger WebAssembly.promising or WebAssembly.Suspending behavior where feasible, and run untrusted code behind stronger isolation boundaries such as separate processes, containers, or equivalent OS-level sandboxing. Available information indicates there is no effective configuration-only workaround when untrusted scripts must be executed in the affected conditions.

Remediation

Patch, then assume compromise.

Upgrade vm2 to version 3.11.4 or later, which contains the patch for this issue. Replace all deployments of vm2 versions prior to 3.11.4, especially where untrusted JavaScript is executed with async support on runtimes exposing WebAssembly JSPI functionality.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

Community discussion across Reddit, Mastodon, and other social sources.