Arbitrary Local File Read via Component Method Invocation in gradio-app/gradio

Vulnerability Description

An issue was discovered in gradio-app/gradio, where the `/component_server` endpoint improperly allows the invocation of any method on a `Component` class with attacker-controlled arguments. Specifically, by exploiting the `move_resource_to_block_cache()` method of the `Block` class, an attacker can copy any file on the filesystem to a temporary directory and subsequently retrieve it. This vulnerability enables unauthorized local file read access, posing a significant risk especially when the application is exposed to the internet via `launch(share=True)`, thereby allowing remote attackers to read files on the host machine. Furthermore, gradio apps hosted on `huggingface.co` are also affected, potentially leading to the exposure of sensitive information such as API keys and credentials stored in environment variables.

References

• https://huntr.com/bounties/4acf584e-2fe8-490e-878d-2d9bf2698338
• https://github.com/gradio-app/gradio/commit/24a583688046867ca8b8b02959c441818bdb34a2
• https://www.gradio.app/changelog#4-13-0