Gradio is an open-source Python package designed for quick prototyping. Prior to version 6.6.0, a Server-Side Request Forgery (SSRF) vulnerability in Gradio allows an attacker to make arbitrary HTTP requests from a victim's server by hosting a malicious Gradio Space. When a victim application uses `gr.load()` to load an attacker-controlled Space, the malicious `proxy_url` from the config is trusted and added to the allowlist, enabling the attacker to access internal services, cloud metadata endpoints, and private networks through the victim's infrastructure. Version 6.6.0 fixes the issue.

Affected: PyPI: gradio

### Summary

A Server-Side Request Forgery (SSRF) vulnerability in Gradio allows an attacker to make arbitrary HTTP requests from a victim's server by hosting a malicious Gradio Space. When a victim application uses `gr.load()` to load an attacker-controlled Space, the malicious `proxy_url` from the config is trusted and added to the allowlist, enabling the attacker to access internal services, cloud metadata endpoints, and private networks through the victim's infrastructure.

### Details

The vulnerability exists in Gradio's config processing flow when loading external Spaces:

1. **Config Fetching** (`gradio/external.py:630`): `gr.load()` calls `Blocks.from_config()` which fetches and processes the remote Space's configuration.

2. **Proxy URL Trust** (`gradio/blocks.py:1231-1233`): The `proxy_url` from the untrusted config is added directly to `self.proxy_urls`: ```python if config.get("proxy_url"): self.proxy_urls.add(config["proxy_url"]) ```

3. **Built-in Proxy Route** (`gradio/routes.py:1029-1031`): Every Gradio app automatically exposes a `/proxy={url_path}` endpoint: ```python @router.get("/proxy={url_path:path}", dependencies=[Depends(login_check)]) async def reverse_proxy(url_path: str): ```

4. **Host-based Validation** (`gradio/routes.py:365-368`): The validation only checks if the URL's host matches any trusted `proxy_url` host: ```python is_safe_url = any( url.host == httpx.URL(root).host for root in self.blocks.proxy_…

Affected: PyPI: gradio

Gradio is an open-source Python package designed for quick prototyping. Prior to version 6.6.0, a Server-Side Request Forgery (SSRF) vulnerability in Gradio allows an attacker to make arbitrary HTTP requests from a victim's server by hosting a malicious Gradio Space. When a victim application uses `gr.load()` to load an attacker-controlled Space, the malicious `proxy_url` from the config is trusted and added to the allowlist, enabling the attacker to access internal services, cloud metadata endpoints, and private networks through the victim's infrastructure. Version 6.6.0 fixes the issue.