CVE-2026-47137 Elastic Security · Elastic

Detect CVE-2026-47137 — vm2 Sandbox Escape via nesting:true Bypass (RCE) in Elastic Security

Detects exploitation of CVE-2026-47137, a critical sandbox escape vulnerability in the vm2 Node.js library (<=3.11.3). This bypass circumvents the CVE-2023-37903 patch by abusing the nesting:true configuration option without an explicit require, enabling full remote code execution from within a sandboxed context. CVSS 10.0.

MITRE ATT&CK

Tactic
Execution Privilege Escalation Lateral Movement

Elastic Detection Query

Elastic Security (Elastic)
eql 
sequence by host.name, process.parent.entity_id with maxspan=2m
  [process where event.type == "start"
   and process.name : ("node", "node.exe", "nodejs")
   and (process.args : "*vm2*" or process.command_line : "*nesting*true*" or process.command_line : "*sandbox*")
  ]
  [process where event.type == "start"
   and (
     process.name : ("sh", "bash", "dash", "zsh", "cmd.exe", "powershell.exe", "pwsh.exe", "python*", "perl*", "ruby*")
     or process.command_line : ("*child_process*", "*execSync*", "*spawnSync*", "*execFileSync*")
   )
  ]
| head 500
critical severity high confidence

EQL sequence rule detecting a Node.js process referencing vm2 or nesting sandbox options followed within two minutes by a shell or interpreter spawn, which is the characteristic post-exploitation behavior of CVE-2026-47137.

Data Sources

Elastic SIEMElastic Endpoint SecurityFilebeat with Sysmon module

Required Tables

logs-endpoint.events.process-*logs-system.syslog-*

False Positives & Tuning

  • Monorepo build tools using vm2 for isolated script evaluation that shell out to package managers
  • Serverless function frameworks that sandbox user code via vm2 and legitimately start child processes for request handling
  • Node.js test harnesses that use vm2 and spawn interpreter subprocesses to validate sandbox isolation

Other platforms for CVE-2026-47137

Microsoft Sentinel (KQL) Splunk (SPL) IBM QRadar (QRadar) Sumo Logic CSE (Sumo) Google Chronicle (YARA-L) CrowdStrike LogScale (LogScale) All platforms (combined) →

Testing Methodology

Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.

  1. Test 1vm2 nesting:true Sandbox Escape via CVE-2026-47137

    Expected signal: Sysmon EventID 1 showing node process spawning with vm2 in command line; child_process.execSync call visible in process arguments; file creation event for /tmp/vm2_escape_proof.txt

  2. Test 2vm2 Vulnerable Version Installation and Verification

    Expected signal: npm install process spawning with [email protected] argument; file creation events under /tmp/vm2_test/node_modules/vm2/; network connection to npm registry (registry.npmjs.org:443)

  3. Test 3vm2 Reverse Shell Simulation Post-Escape

    Expected signal: Network connection from node process to 127.0.0.1:9999 (or configured beacon host); curl child process spawned from Node.js parent; DNS/HTTP request with CVE identifier in URI path

  4. Test 4vm2 nesting Bypass with Prototype Chain Traversal (Variant)

    Expected signal: Node.js process with vm2 in command line; fs.writeFileSync call resulting in file creation event at /tmp/vm2_variant_proof.txt; no child process spawned in this variant

Last updated: 2026-06-21 Research depth: standard
References (6)

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Tactic Hubs

TA0002ExecutionTA0004Privilege EscalationTA0008Lateral Movement

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