JupyterLab Desktop up to 4.6.2-0 Renderer improper authentication

Summaryinfo

A vulnerability labeled as critical has been found in JupyterLab Desktop up to 4.6.2-0. Affected is an unknown function of the component Renderer. Such manipulation leads to improper authentication. This vulnerability is traded as CVE-2026-86044. The attack may be launched remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in JupyterLab Desktop up to 4.6.2-0. It has been rated as critical. Affected by this issue is an unknown part of the component Renderer. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is confidentiality, integrity, and availability. CVE summarizes:

JupyterLab Desktop is the cross-platform desktop application for JupyterLab. Prior to 4.6.2-1, JupyterLab Desktop exposed getServerInfo to the renderer without confirming that the current page still had the local Jupyter server origin. In a local managed session using JupyterLab before 4.4.8, an attacker can place a crafted MathJax link in an untrusted notebook. If a victim opens the notebook and clicks the link, the existing renderer navigates to an attacker-controlled site while retaining access to the preload bridge. The site can call getServerInfo to obtain the local server URL and authentication token, then use the Jupyter REST API to create and trust a notebook that executes arbitrary code as the victim. Users whose environment already uses JupyterLab 4.4.8 or later are unaffected because the corrected link handling breaks the first step of the chain. This vulnerability is fixed in 4.6.2-1.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-86044 since 09/04/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available.

Upgrading to version 4.6.2-1 eliminates this vulnerability.

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Productinfo

Vendor

• JupyterLab

Name

• Desktop

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6.2-0

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