CVE-2026-73417

Received Received - Intake

Arbitrary Code Execution in JupyterLab Settings

Publication date: 2026-08-13

Last updated on: 2026-08-13

Assigner: GitHub, Inc.

Description

jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 3.3.0 until 4.5.10 and 4.6.2, JupyterLab allows notebook settings to be shared and applied through an overrides.json file using the Import button in the Settings Editor. In packages/notebook-extension/schema/tracker.json and packages/notebook-extension/src/index.ts, the sideBySideLeftMarginOverride and sideBySideRightMarginOverride settings are not properly validated before being inserted into style content, allowing a crafted settings file to contain instructions that execute as code instead of only changing display preferences. A user can import the malicious file, or an attacker with access to a shared settings location can plant an overrides.json that is applied automatically. The embedded code runs with the affected user's access and can read or modify notebooks and files and run code through the notebook server, including on a connected kernel. This issue is fixed in versions 4.5.10 and 4.6.2.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-13

Last Modified

2026-08-13

Generated

2026-08-14

AI Q&A

2026-08-14

EPSS Evaluated

N/A

NVD

CVE-2026-73417

Affected Vendors & Products

Vendor	Product	Version / Range
jupyterlab	jupyterlab	From 3.3.0 (inc) to 4.5.10 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CWE-116	The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.

Attack-Flow Graph

Executive Summary

JupyterLab versions between 3.3.0 and 4.5.10 and 4.6.2 have a flaw where settings imported via overrides.json are not properly validated. Specifically, the sideBySideLeftMarginOverride and sideBySideRightMarginOverride settings can execute malicious code instead of just changing display settings. This allows attackers to run arbitrary code with the user's permissions.

Detection Guidance

Check for unauthorized overrides.json files in JupyterLab settings directories, particularly in packages/notebook-extension/schema/ and packages/notebook-extension/src/. Inspect style content for executable code instead of valid CSS. Review user-imported settings files for suspicious content.

Impact Analysis

If exploited, this vulnerability allows attackers to read or modify notebooks and files, execute code on the notebook server, and interact with connected kernels. This could lead to data theft, unauthorized code execution, or further compromise of the system.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating GDPR's data protection requirements and HIPAA's safeguards for protected health information. Organizations may face compliance breaches, legal penalties, and reputational damage if exploited.

Mitigation Strategies

Upgrade JupyterLab to version 4.5.10, 4.6.2, or later. Remove any untrusted overrides.json files. Restrict write access to shared settings locations. Monitor for unauthorized changes to notebook files or server behavior.

Hi! I’m here to help you understand CVE-2026-73417. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70