Bug 2515831 (CVE-2026-73417)

Summary: CVE-2026-73417 jupyterlab: JupyterLab: Cross-site scripting (XSS) allows arbitrary code execution
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rjohnson
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in JupyterLab. Improper validation of `sideBySideLeftMarginOverride` and `sideBySideRightMarginOverride` settings within the `overrides.json` file allows for cross-site scripting (XSS). An attacker can exploit this by convincing a user to import a specially crafted settings file, or by placing such a file in a shared settings location. Successful exploitation can lead to arbitrary code execution, enabling the attacker to read or modify notebooks and files, and run code through the notebook server.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-13 22:23:33 UTC 
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.