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TI-2024-23295 Aliases CVE-2024-35225GHSA-fvcq-4x64-hqxr

Jupyter Server Proxy has a reflected XSS issue in host parameter

Priority MEDIUM 43CWE-116Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00442 38th percentileScored 2026-11-07
Fix Fixed jupyter-server-proxy (jupyterhub): 3.2.4, 4.2.0jupyter-server-proxy (PyPI): 3.2.4, 4.2.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
jupyterhubjupyter-server-proxy3.0.0 to before 3.2.4; 4.0.0 to before 4.2.03.2.4, 4.2.0Patch availableCNA
—jupyter-server-proxy (PyPI)3.0.0 to before 3.2.43.2.4Patch availableGHSA-fvcq-4x64-hqxr
—jupyter-server-proxy (PyPI)4.0.0 to before 4.2.04.2.0Patch availableGHSA-fvcq-4x64-hqxr
  • jupyter-server-proxy Vendorjupyterhub Affected 3.0.0 to before 3.2.4; 4.0.0 to before 4.2.0 Fixed in 3.2.4, 4.2.0 Patch available CNA
  • jupyter-server-proxy (PyPI) Vendor— Affected 3.0.0 to before 3.2.4 Fixed in 3.2.4 Patch available GHSA-fvcq-4x64-hqxr
  • jupyter-server-proxy (PyPI) Vendor— Affected 4.0.0 to before 4.2.0 Fixed in 4.2.0 Patch available GHSA-fvcq-4x64-hqxr

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:jupyter:jupyter_server_proxy:*:*:*:*:*:*:*:*3.0.0 to before 3.2.4; 4.1.2 to before 4.2.0Vulnerablejupyterlab
  • cpe:2.3:a:jupyter:jupyter_server_proxy:*:*:*:*:*:*:*:* Versions 3.0.0 to before 3.2.4; 4.1.2 to before 4.2.0 Vulnerable ·jupyterlab

Remediation

  • Fix · CNA jupyter-server-proxy (jupyterhub) Fixed in 3.2.4, 4.2.0
  • Fix · GHSA-fvcq-4x64-hqxr jupyter-server-proxy (PyPI) Fixed in 3.2.4 Advisory →
  • Fix · GHSA-fvcq-4x64-hqxr jupyter-server-proxy (PyPI) Fixed in 4.2.0 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2024-35225
  2. 2026-10-03 Alias added: GHSA-fvcq-4x64-hqxr

References

Patch 2

Advisory 2

Other 3

  • TI-2025-23499 Jupyter Remote Desktop Proxy makes TigerVNC accessible via the network and not just via a UNIX socket as intended CVSS 4.0CRITICAL 9.0
  • TI-2023-10877 JupyterHub's LTI13Authenticator: JWT signature not validated CVSS 3.1CRITICAL 10.0
  • TI-2021-16545 Remote code execution in Binderhub CVSS 3.1CRITICAL 9.8
  • TI-2021-18033 Improper Access Control in jupyterhub-firstuseauthenticator CVSS 3.1CRITICAL 9.8
  • TI-2021-16546 Code injection in nbgitpuller CVSS 3.1CRITICAL 9.6
  • TI-2024-18755 Jupyter Server Proxy's Websocket Proxying does not require authentication CVSS 3.1CRITICAL 9.8
See all 23 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences