# [CRIT] [GHSA / CRITICAL] CVE-2026-47210: vm2 sandbox escape via JSPI-backed Promise `.finally()` species bypass

**Source:** GitHub Security Advisories
**Published:** 2026-05-29
**Article:** https://github.com/advisories/GHSA-6j2x-vhqr-qr7q

## Threat Profile

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

### Summary
A sandbox escape vulnerability in `vm2` allows arbitrary code execution in the host process when untrusted code is executed with async support on runtimes exposing WebAssembly JSPI (`WebAssembly.promising` / `WebAssembly.Suspending`). In the tested configuration, a JSPI-backed Promise can reach `Promise.prototype.finally()` in a way that bypasses the expected Promise-species hardening and exposes a host-originate…

## Indicators of Compromise (high-fidelity only)

- **CVE:** `CVE-2026-47210`

## MITRE ATT&CK Techniques

- **T1190** — Exploit Public-Facing Application
- **T1204.002** — User Execution: Malicious File
- **T1059** — Command and Scripting Interpreter
- **T1068** — Exploitation for Privilege Escalation
- **T1611** — Escape to Host
- **T1592.002** — Gather Victim Host Information: Software

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### Node.js process spawns shell or LOLBin — vm2 sandbox escape post-exploitation (CVE-2026-47210)

`UC_174_2` · phase: **exploit** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime values(Processes.process) as cmdline values(Processes.process_hash) as hash from datamodel=Endpoint.Processes where (Processes.parent_process_name="node.exe" OR Processes.parent_process_name="node") (Processes.process_name="cmd.exe" OR Processes.process_name="powershell.exe" OR Processes.process_name="pwsh.exe" OR Processes.process_name="sh" OR Processes.process_name="bash" OR Processes.process_name="dash" OR Processes.process_name="zsh" OR Processes.process_name="wscript.exe" OR Processes.process_name="cscript.exe" OR Processes.process_name="mshta.exe") by host Processes.user Processes.parent_process Processes.parent_process_path Processes.process_name Processes.process Processes.process_path | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where InitiatingProcessFileName =~ "node.exe" or InitiatingProcessFileName =~ "node"
| where FileName in~ ("cmd.exe","powershell.exe","pwsh.exe","sh","bash","dash","zsh","wscript.exe","cscript.exe","mshta.exe","rundll32.exe")
| where AccountName !endswith "$"
| project Timestamp, DeviceName, AccountName,
          ParentImage = InitiatingProcessFolderPath,
          ParentCmd   = InitiatingProcessCommandLine,
          ChildImage  = FolderPath,
          ChildCmd    = ProcessCommandLine,
          SHA256
| order by Timestamp desc
```

### Vulnerable vm2 (<= 3.11.3) present on host — CVE-2026-47210 exposure

`UC_174_3` · phase: **recon** · confidence: **Medium** · 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 filepath from datamodel=Endpoint.Filesystem where Filesystem.file_path="*\\node_modules\\vm2\\package.json" OR Filesystem.file_path="*/node_modules/vm2/package.json" by host Filesystem.user | `drop_dm_object_name(Filesystem)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
let VulnByTvm = DeviceTvmSoftwareVulnerabilities
    | where CveId == "CVE-2026-47210"
    | project Timestamp, DeviceId, DeviceName, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel;
let VulnByFile = DeviceFileEvents
    | where Timestamp > ago(30d)
    | where FolderPath has @"\node_modules\vm2\" or FolderPath has "/node_modules/vm2/"
    | where FileName =~ "package.json"
    | summarize FirstSeen = min(Timestamp), LastSeen = max(Timestamp), Paths = make_set(FolderPath, 10) by DeviceId, DeviceName
    | project Timestamp = LastSeen, DeviceId, DeviceName, Evidence = "node_modules/vm2 package.json present", Paths;
VulnByTvm
| union VulnByFile
| order by Timestamp desc
```

### Article-specific behavioural hunt — [GHSA / CRITICAL] CVE-2026-47210: vm2 sandbox escape via JSPI-backed Promise `.f

`UC_174_1` · phase: **exploit** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Article-specific bespoke detection — [GHSA / CRITICAL] CVE-2026-47210: vm2 sandbox escape via JSPI-backed Promise `.f ```
| tstats `summariesonly` count earliest(_time) AS firstTime latest(_time) AS lastTime
    from datamodel=Endpoint.Processes
    where (Processes.process_name IN ("node.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 ("node.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-2026-47210: vm2 sandbox escape via JSPI-backed Promise `.f
// 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~ ("node.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~ ("node.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-2026-47210`


## 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.