Vulnerability Database

394,002

Total vulnerabilities in the database

HTML injection in JupyterLite leading to DOM Clobbering — jupyterlite-core

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Impact

The vulnerability depends on user interaction by opening a malicious notebook with Markdown cells, or Markdown file using JupyterLab preview feature.

A malicious user can access any data accessible from JupyterLite and perform arbitrary actions in JupyterLite environment.

Patches

JupyterLite 0.4.1 was patched.

Workarounds

There is no workaround for the underlying DOM Clobbering susceptibility. However, select plugins can be disabled on deployments which cannot update in a timely fashion to minimise the risk. These are:

  • @jupyterlab/mathjax-extension:plugin - users will loose ability to preview mathematical equations
  • @jupyterlab/markdownviewer-extension:plugin - users will loose ability to open Markdown previews
  • @jupyterlab/mathjax2-extension:plugin (if installed with optional jupyterlab-mathjax2 package) - an older version of the mathjax plugin for JupyterLab 4.x

To disable these extensions populate the disabledExtensions key in jupyter-config-data stanza of jupyter-lite.json as documented on https://jupyterlite.readthedocs.io/en/stable/howto/configure/config_files.html#jupyter-lite-json

{ "jupyter-lite-schema-version": 0, "jupyter-config-data": { "appName": "My JupyterLite App", "disabledExtensions": [ "@jupyterlab/markdownviewer-extension:plugin", "@jupyterlab/mathjax-extension:plugin", "@jupyterlab/mathjax2-extension:plugin" ] } }

To confirm that the plugins were disabled manual inspection of the built page is required.

References

Upstream advisory: https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-9q39-rmj3-p4r2

Notes

This change has a potential to break rendering of some markdown. There is a setting in Sanitizer which allows to revert to the previous sanitizer settings (allowNamedProperties).

  • Published: Sep 6, 2024
  • Updated: Jun 5, 2026
  • GHSA: GHSA-gj55-2xf9-67rq
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: High
  • Score: 8.1
  • AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

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Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

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