CVE-2026-92957 — vm2 through 3.11.6 does not normalize `node:`-prefixed builtin specifiers when evaluating…¶

Key facts

CVE-2026-92957 is a Critical (9.9) vulnerability: vm2 through 3.11.6 does not normalize node:-prefixed builtin specifiers when evaluating…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-92957
Severity	Critical (9.9)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-92957/

Details¶

English | 한국어

Description¶

vm2 through 3.11.6 does not normalize node:-prefixed builtin specifiers when evaluating user-supplied negative (deny) entries in a NodeVM wildcard require policy. Although NodeVM strips the node: prefix during require() resolution, negative wildcard entries are matched by exact string comparison against the canonical builtin names, so a policy such as new NodeVM({ require: { builtin: ['*', '-node:child_process'] } }) fails to deny the canonical child_process module. Sandboxed code can therefore obtain the host child_process builtin via require('child_process') or require('node:child_process'), gaining references to process-spawning APIs such as execSync and spawn, which is equivalent to host command-execution capability for untrusted sandbox code. Fixed in vm2 3.11.7. (Suggested title: "vm2 before 3.11.7: NodeVM builtin deny-list bypass via node:-prefixed specifiers exposes child_process")

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-92957
CVSS Score	9.9

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-92957/poc.py

Usage¶

# Run PoC against target
python3 poc.py --target <TARGET_URL>

# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>

⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.

Test Lab¶

This repository includes a Docker-based test environment with both vulnerable and patched applications.

Quick Start¶

# Clone and navigate to CVE directory
cd CVE-2026-92957

# Start both applications
docker-compose up -d

# Run tests
./run-tests.sh    # Linux/Mac
./run-tests.ps1   # Windows PowerShell

Application Endpoints¶

Application	URL	Status
Vulnerable App	http://localhost:8080	Shows vulnerability
Patched App	http://localhost:8081	Demonstrates fix

Directory Structure¶

├── README.md           # English documentation
├── README_KO.md        # Korean documentation
├── poc.py              # PoC detection script
├── docker-compose.yml  # Container orchestration
├── run-tests.sh        # Linux/Mac test runner
├── run-tests.ps1       # Windows test runner
├── vulnerable-app/     # Vulnerable version
│   ├── app.py
│   ├── Dockerfile
│   └── requirements.txt
└── patched-app/        # Fixed version
    ├── app.py
    ├── Dockerfile
    └── requirements.txt

References¶

https://github.com/patriksimek/vm2/security/advisories/GHSA-8686-vhfx-7r3j
https://www.vulncheck.com/advisories/vm2-before-3.11.7-authentication-bypass-via-node-prefix

Generated by PoC Generator on 2026-09-18T00:12:47.294831883

Frequently asked questions¶

What is CVE-2026-92957?¶