Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.8.0, the profile_image_url field on the user profile update form accepted arbitrary data: URI values without MIME-type validation, resulting in a XSS vulnerability. This vulnerability is fixed in 0.8.0.

Affected: PyPI: open-webui

## Summary

The `profile_image_url` field on the user profile update form accepted arbitrary `data:` URI values without MIME-type validation. Two distinct attack paths were independently demonstrated by separate reporters:

1. **`data:text/html;base64,...` in a new browser tab** (raresvis, 2025-04-17) — when a victim right-clicks a user's profile picture and chooses "Open image in new tab", the browser navigates to the data: URL and executes embedded scripts in the `data:` origin. Limited to social-engineering / redirect attacks because the script does not run in the application origin.

2. **`data:image/svg+xml;base64,...` re-served by the application origin** (Gh05t666nero, 2026-01-09) — `GET /api/v1/users/{user_id}/profile/image` decoded the base64 and returned `StreamingResponse(media_type=<user-controlled>)` extracted from the `data:` header. With `media_type=image/svg+xml` and `Content-Disposition: inline`, the SVG-embedded scripts executed in the **application origin**, enabling JWT theft from `localStorage` and full account takeover of any user — including admins — who loaded the malicious profile image URL.

Both attack paths share the same root cause (lack of MIME-type validation on `profile_image_url`) and are closed by the same fix.

## Vulnerable code (v0.7.0)

`backend/open_webui/routers/users.py` `get_user_profile_image_by_id()`:

```python elif user.profile_image_url.startswith("data:image"): header, base64_data = user.profile_image_url.split(",", 1)…

Affected: PyPI: open-webui

## Summary

The `profile_image_url` field on the user profile update form accepted arbitrary `data:` URI values without MIME-type validation. Two distinct attack paths were independently demonstrated by separate reporters:

1. **`data:text/html;base64,...` in a new browser tab** (raresvis, 2025-04-17) — when a victim right-clicks a user's profile picture and chooses "Open image in new tab", the browser navigates to the data: URL and executes embedded scripts in the `data:` origin. Limited to social-engineering / redirect attacks because the script does not run in the application origin.

2. **`data:image/svg+xml;base64,...` re-served by the application origin** (Gh05t666nero, 2026-01-09) — `GET /api/v1/users/{user_id}/profile/image` decoded the base64 and returned `StreamingResponse(media_type=<user-controlled>)` extracted from the `data:` header. With `media_type=image/svg+xml` and `Content-Disposition: inline`, the SVG-embedded scripts executed in the **application origin**, enabling JWT theft from `localStorage` and full account takeover of any user — including admins — who loaded the malicious profile image URL.

Both attack paths share the same root cause (lack of MIME-type validation on `profile_image_url`) and are closed by the same fix.

## Vulnerable code (v0.7.0)

`backend/open_webui/routers/users.py` `get_user_profile_image_by_id()`:

```python elif user.profile_image_url.startswith("data:image"): header, base64_data = user.profile_image_url.split(",", 1)…