# CVE-2024-35225: Jupyter Server Proxy has a reflected XSS issue in host parameter

Source: https://junglewise.ai/threats/cve-2024-35225-jupyter-server-proxy-has-a-reflected-xss-issue-in-host-parameter  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2024-06-11  
License: CC BY 4.0 with a link back

CVE-2024-35225 · Severity: low · CVSS 3.1 · Published 2024-06-11

Jupyter Server Proxy allows users to run arbitrary external processes alongside their notebook server and provide authenticated web access to them. Versions of 3.x prior to 3.2.4 and 4.x prior to 4.2.0 have a reflected cross-site scripting (XSS) issue. The `/proxy` endpoint accepts a `host` path segment in the format `/proxy/<host>`. When this endpoint is called with an invalid `host` value, `jupyter-server-proxy` replies with a response that includes the value of `host`, without sanitization [2]. A third-party actor can leverage this by sending a phishing link with an invalid `host` value containing custom JavaScript to a user. When the user clicks this phishing link, the browser renders the response of `GET /proxy/<host>`, which runs the custom JavaScript contained in `host` set by the actor. As any arbitrary JavaScript can be run after the user clicks on a phishing link, this issue permits extensive access to the user's JupyterLab instance for an actor. Patches are included in versions 4.2.0 and 3.2.4. As a workaround, server operators who are unable to upgrade can disable the `jupyter-server-proxy` extension.

Technologies: [jupyter-server-proxy (PyPI)](https://junglewise.ai/threats/technologies/jupyter-server-proxy). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2024-35225 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2024-35225 being exploited in the wild.

**How severe is CVE-2024-35225?** Low severity, with a CVSS score of 3.1, published 11 June 2024.

**Which products and versions are affected?** jupyter-server-proxy (PyPI) ECOSYSTEM:introduced=3.0.0,fixed=3.2.4, GIT:introduced=0,fixed=7abc9dc5bbb0b4b440548a5375261b8b8192fc22,fixed=ff78128087e73fb9d0909e1366f8bf051e8ea878|ECOSYSTEM:introduced=3.0.0,fixed=3.2.4,introduced=4.1.2,fixed=4.2.0.

**Is there a fix for CVE-2024-35225?** Yes. jupyter-server-proxy (PyPI): upgrade to 3.2.4, 4.2.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2024-35225?** Check whether you run jupyter-server-proxy (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

- jupyter-server-proxy (PyPI): upgrade to 3.2.4, 4.2.0 or later

  ```sh
  pip install "jupyter-server-proxy>=4.2.0"
  ```


## Affected products

- jupyter-server-proxy (PyPI) ECOSYSTEM:introduced=3.0.0,fixed=3.2.4, GIT:introduced=0,fixed=7abc9dc5bbb0b4b440548a5375261b8b8192fc22,fixed=ff78128087e73fb9d0909e1366f8bf051e8ea878|ECOSYSTEM:introduced=3.0.0,fixed=3.2.4,introduced=4.1.2,fixed=4.2.0

## Identifiers

- CVE-2024-35225
- GHSA-fvcq-4x64-hqxr
- PYSEC-2024-236

## Related threats

- [Jupyter Server Proxy's Websocket Proxying does not require authentication](https://junglewise.ai/threats/cve-2024-28179-jupyter-server-proxy-s-websocket-proxying-does-not-require)
- [SSRF vulnerability in jupyter-server-proxy](https://junglewise.ai/threats/cve-2022-21697-ssrf-vulnerability-in-jupyter-server-proxy)