# [CRIT] [GHSA / CRITICAL] CVE-2026-47137: vm2 has a CVE-2023-37903 patch bypass: nesting:true without explicit require still allows full RCE

**Source:** GitHub Security Advisories
**Published:** 2026-05-29
**Article:** https://github.com/advisories/GHSA-m4wx-m65x-ghrr

## Threat Profile

vm2 has a CVE-2023-37903 patch bypass: nesting:true without explicit require still allows full RCE

## Summary

The fix for GHSA-8hg8-63c5-gwmx (CVE-2023-37903) introduced a check in `nodevm.js` line 263 that blocks the combination `nesting: true` + `require: false`. However, the check uses strict equality (`options.require === false`), which is trivially bypassed by omitting the `require` option entirely.

When `require` is not specified, `options.require` is `undefined`, not `false`. The stric…

## Indicators of Compromise (high-fidelity only)

- **CVE:** `CVE-2026-47137`
- **CVE:** `CVE-2023-37903`

## MITRE ATT&CK Techniques

- **T1190** — Exploit Public-Facing Application
- **T1204.002** — User Execution: Malicious File
- **T1059.003** — Command and Scripting Interpreter: Windows Command Shell
- **T1059.004** — Command and Scripting Interpreter: Unix Shell
- **T1611** — Escape to Host
- **T1059.007** — Command and Scripting Interpreter: JavaScript

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### Node.js process spawning OS shell with enumeration commands — vm2 sandbox escape (CVE-2026-47137)

`UC_175_2` · phase: **exploit** · confidence: **Medium** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime values(Processes.process) as cmdlines from datamodel=Endpoint.Processes where (Processes.parent_process_name="node.exe" OR Processes.parent_process_name="node") AND (Processes.process_name IN ("cmd.exe","powershell.exe","pwsh.exe","sh","bash","dash","ash","zsh","wmic.exe")) AND (Processes.process="*whoami*" OR Processes.process="* id*" OR Processes.process="*uname*" OR Processes.process="*hostname*" OR Processes.process="*ipconfig*" OR Processes.process="*ifconfig*" OR Processes.process="*/etc/passwd*" OR Processes.process="*child_process*" OR Processes.process="*execSync*" OR Processes.process="*net user*" OR Processes.process="*cat /etc*") by Processes.dest Processes.user Processes.parent_process Processes.parent_process_name Processes.process Processes.process_name | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where InitiatingProcessFileName in~ ("node.exe", "node")
| where FileName in~ ("cmd.exe", "powershell.exe", "pwsh.exe", "sh", "bash", "dash", "ash", "zsh", "wmic.exe")
| where ProcessCommandLine has_any ("whoami", " id ", " id;", "uname", "hostname", "ipconfig", "ifconfig", "/etc/passwd", "/etc/shadow", "child_process", "execSync", "net user", "cat /etc", "systeminfo")
| where AccountName !endswith "$"
| project Timestamp, DeviceName, AccountName,
          ParentImage = InitiatingProcessFolderPath,
          ParentCmd = InitiatingProcessCommandLine,
          ChildImage = FolderPath,
          ChildCmd = ProcessCommandLine,
          SHA256
| order by Timestamp desc
```

### Vulnerable vm2 package (<=3.11.3) present on host — CVE-2026-47137 exposure surface

`UC_175_3` · phase: **weapon** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime values(Filesystem.file_path) as paths from datamodel=Endpoint.Filesystem where Filesystem.file_path="*\\node_modules\\vm2\\package.json" OR Filesystem.file_path="*/node_modules/vm2/package.json" OR Filesystem.file_path="*\\node_modules\\vm2\\lib\\nodevm.js" OR Filesystem.file_path="*/node_modules/vm2/lib/nodevm.js" by Filesystem.dest Filesystem.user Filesystem.file_path Filesystem.file_name | `drop_dm_object_name(Filesystem)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
DeviceFileEvents
| where Timestamp > ago(90d)
| where FolderPath has_any (@"\node_modules\vm2\", "/node_modules/vm2/")
| where FileName in~ ("package.json", "nodevm.js", "main.js", "index.js")
| summarize FirstSeen = min(Timestamp),
            LastSeen  = max(Timestamp),
            Paths     = make_set(FolderPath, 20),
            Files     = make_set(FileName, 10),
            Writers   = make_set(InitiatingProcessFileName, 10)
  by DeviceName
| extend NodeAppHost = iff(array_length(Paths) > 0, true, false)
| order by LastSeen desc
```

### Article-specific behavioural hunt — [GHSA / CRITICAL] CVE-2026-47137: vm2 has a CVE-2023-37903 patch bypass: nesting

`UC_175_1` · phase: **exploit** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Article-specific bespoke detection — [GHSA / CRITICAL] CVE-2026-47137: vm2 has a CVE-2023-37903 patch bypass: nesting ```
| tstats `summariesonly` count earliest(_time) AS firstTime latest(_time) AS lastTime
    from datamodel=Endpoint.Processes
    where (Processes.process_name IN ("nodevm.js","exploit.js"))
    by Processes.dest, Processes.user, Processes.process_name,
       Processes.process, Processes.parent_process_name, Processes.process_path
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| append [
| tstats `summariesonly` count
    from datamodel=Endpoint.Filesystem
    where Filesystem.action IN ("created","modified")
      AND (Filesystem.file_name IN ("nodevm.js","exploit.js"))
    by Filesystem.dest, Filesystem.user, Filesystem.process_name,
       Filesystem.file_path, Filesystem.file_name
| `drop_dm_object_name(Filesystem)`
]
```

**Defender KQL:**
```kql
// Article-specific bespoke detection — [GHSA / CRITICAL] CVE-2026-47137: vm2 has a CVE-2023-37903 patch bypass: nesting
// Hunts the actual binaries / paths / commandline fragments named
// in the article instead of a generic technique-class template.
DeviceProcessEvents
| where Timestamp > ago(30d)
| where (FileName in~ ("nodevm.js", "exploit.js"))
| project Timestamp, DeviceName, AccountName, FileName,
          FolderPath, ProcessCommandLine,
          InitiatingProcessFileName, InitiatingProcessCommandLine
| order by Timestamp desc

// File-creation events for the named binaries / paths
DeviceFileEvents
| where Timestamp > ago(30d)
| where ActionType in ("FileCreated","FileModified")
| where (FileName in~ ("nodevm.js", "exploit.js"))
| project Timestamp, DeviceName, AccountName, FolderPath,
          FileName, ActionType, InitiatingProcessFileName,
          InitiatingProcessCommandLine
| order by Timestamp desc
```

### IOC-driven hunts (use shared templates)

These are standard IOC-substitution hunts — the canonical SPL and KQL live once in [`_TEMPLATES.md`](../_TEMPLATES.md), so we don't repeat the same boilerplate on every CVE / hash / network-IOC briefing.

- **Asset exposure — vulnerability matches article CVE(s)** ([template](../_TEMPLATES.md#asset-exposure)) — phase: **recon**, confidence: **High**
  - CVE(s): `CVE-2026-47137`, `CVE-2023-37903`


## Why this matters

Severity classified as **CRIT** based on: CVE present, 4 use case(s) fired, 6 technique(s) inferred. Read the full article for actor attribution, tooling details, and any defanged IOCs in the body that aren't visible in the RSS summary.