Open WebUI: Open WebUI has Blind Server Side Request Forgery in its Image Edit Functionality

Summary

There is a blind server side request forgery in the functionality that allows editing an image via a prompt. The affected function will perform a GET request on the URL provided by the user. There is no restriction on the domain of the provided URL allowing the local address space to be interacted with. Since the SSRF is blind (the response cannot be read) impact is port scanning of the local network because it can be confirmed if the port is open based on if the GET request failed.

Details

The vulnerability occurs here: https://github.com/open-webui/open-webui/blob/2b26355002064228e9b671339f8f3fb9d1fafa73/backend/open_webui/routers/images.py#L850-L916 Line 911 shows the user provided URL passed to the function load_url_image. Within this function on line 883 HTTP/HTTPs URLs are trusted blindly and called asynchronously with requests.get.

PoC

The vulnerability can be reproduced with the following curl command:

curl -X POST http://localhost:3000/api/v1/images/edit \
  -H "Authorization: Bearer <token>" \
  -H "Content-Type: application/json" \
  -d '{"form_data":{
    "image": "<url>",
    "prompt": "poc"}
  }'

Impact

Response differentials can be used to port scan the local network: <img width="3016" height="736" alt="image" src="https://github.com/user-attachments/assets/93b4df52-b23c-4ed7-a5fa-9cbedb30091c" /> This can be automated to iterate through the entire port range to determine open ports. If the service running on an open port can be inferred the user may be able to interact with it in a meaningful way if the service offers any state changing GET request endpoints.

Remediation

Restrict provided URLs from local address space.