CVE-2026-92958 — vm2 through 3.11.6 contains a builtin-module denylist bypass in NodeVM.¶

Key facts

CVE-2026-92958 is a High (8.5) vulnerability: vm2 through 3.11.6 contains a builtin-module denylist bypass in NodeVM.. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-92958
Severity	High (8.5)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-92958/

Details¶

English | 한국어

Description¶

vm2 through 3.11.6 contains a builtin-module denylist bypass in NodeVM. When the embedder uses the builtin wildcard together with negative entries (e.g. require: { builtin: ['*', '-fs', '-child_process'] }), negative entries are matched by exact module name in lib/builtin.js, so -fs removes only the builtin named fs and does not remove builtin subpaths such as fs/promises. Sandboxed code can therefore call require('fs/promises') or require('node:fs/promises') and reach the promise-based filesystem API despite fs being denied; node: prefix handling is likewise inconsistent (a -node:fs/promises entry does not block require('fs/promises')). Host file creation and writing were confirmed via fsp.writeFile(), and other fs/promises operations (cp, mkdir, rename, rm, rmdir, truncate, read operations, etc.) are also reachable. This issue is fixed in vm2 3.11.7.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-92958
CVSS Score	8.5

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-92958/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-2026-92958

# 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-6rh5-qq4q-97xh
https://www.vulncheck.com/advisories/vm2-before-3.11.7-denylist-bypass-via-fs-promises

Generated by PoC Generator on 2026-09-18T00:03:08.940079041

Frequently asked questions¶

What is CVE-2026-92958?¶

CVE-2026-92958 is a High (8.5) vulnerability: vm2 through 3.11.6 contains a builtin-module denylist bypass in NodeVM.. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-92958?¶

Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.

How do I block or mitigate CVE-2026-92958?¶

Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.

For authorized security testing and research only. See the full source and NVD record.