# CVE-2026-70486: Open WebUI same-origin XSS in terminal file preview

Source: https://junglewise.ai/threats/cve-2026-70486-open-webui-same-origin-xss-in-terminal-file-preview  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-04. Updated: 2026-08-04  
License: CC BY 4.0 with a link back

CVE-2026-70486 · Severity: high · CVSS 8.2 · Published 2026-08-04

Open WebUI, a user interface for interacting with large language models, contains a security flaw in how it previews files from terminal servers. An authenticated attacker can create a malicious file that, when automatically previewed by another user, executes code in that user's browser. This allows the attacker to steal the victim's session token and take over their account, potentially leading to full control over the server if the victim is an administrator.

Technologies: [open-webui (PyPI)](https://junglewise.ai/threats/technologies/open-webui). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-70486 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-70486 being exploited in the wild.

**How severe is CVE-2026-70486?** High severity, with a CVSS score of 8.2, published 4 August 2026.

**Which products and versions are affected?** open-webui (PyPI) >= 0.9.0, <= 0.10.2, ECOSYSTEM:introduced=0.9.0,fixed=0.11.0.

**Is there a fix for CVE-2026-70486?** Yes. open-webui (PyPI): upgrade to 0.11.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-70486 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-70486?** Check whether you run open-webui (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- open-webui (PyPI): upgrade to 0.11.0 or later

  ```sh
  pip install "open-webui>=0.11.0"
  ```


## Technical details

A Cross-Site Scripting (XSS) vulnerability exists in Open WebUI's `FilePreview.svelte` component when rendering files served via the `serveUrl` path. The application uses an iframe to preview terminal-served files but hardcodes the `allow-same-origin` attribute in the sandbox configuration. Because these files are served from the application's own origin (`/api/v1/terminals/{id}/files/serve/...`) and lack a restrictive Content-Security-Policy (CSP) by default, the sandbox provides no isolation. An authenticated attacker with access to a terminal server can upload a malicious HTML file and trigger a `display_file` tool call; when the victim views the chat, the script executes in the application's origin, allowing it to access `localStorage` and exfiltrate session tokens. This is fixed in version 0.11.0 by making `allow-same-origin` an opt-in setting.

## Affected products

- Open WebUI open-webui >= 0.9.0, <= 0.10.2

## Identifiers

- CVE-2026-70486
- GHSA-3xpf-xq7r-v8c5
- PYSEC-2026-3641

## Timeline

- 2026-08-02: disclosed
- 2026-08-02: patched: Fixed in version 0.11.0
- 2026-08-04: advisory

## References

- [https://api.github.com/users/manus-use](https://api.github.com/users/manus-use)
- [https://github.com/manus-use](https://github.com/manus-use)
- [https://api.github.com/users/manus-use/gists%7B/gist_id%7D](https://api.github.com/users/manus-use/gists%7B/gist_id%7D)
- [https://api.github.com/users/manus-use/repos](https://api.github.com/users/manus-use/repos)
- [https://avatars.githubusercontent.com/u/213290975?v=4](https://avatars.githubusercontent.com/u/213290975?v=4)
- [https://api.github.com/users/manus-use/events%7B/privacy%7D](https://api.github.com/users/manus-use/events%7B/privacy%7D)

## Related threats

- [Open WebUI OAuth token exchange authorization bypass](https://junglewise.ai/threats/cve-2026-88006-open-webui-oauth-token-exchange-authorization-bypass)
- [Open WebUI OAuth token exchange authorization bypass](https://junglewise.ai/threats/cve-2026-88005-open-webui-oauth-token-exchange-authorization-bypass)
- [Open WebUI infinite loop denial of service in chat history reconstruction](https://junglewise.ai/threats/cve-2026-88002-open-webui-infinite-loop-denial-of-service-in-chat-history)
- [Open WebUI server-side request forgery via unvalidated HTTP redirects](https://junglewise.ai/threats/cve-2026-88001-open-webui-server-side-request-forgery-via-unvalidated-http)
- [Open WebUI denial of service via cyclic chat tree message deletion](https://junglewise.ai/threats/cve-2026-88000-open-webui-denial-of-service-via-cyclic-chat-tree-message)