Jupyter notebook up to 4.5.6 cross site scripting

Summaryinfo

A vulnerability, which was classified as problematic, was found in Jupyter notebook up to 4.5.6. The impacted element is an unknown function. Executing a manipulation can lead to cross site scripting. This vulnerability appears as CVE-2026-42557. The attack may be performed from remote. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in Jupyter notebook up to 4.5.6 and classified as problematic. This vulnerability affects some unknown functionality. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect integrity. CVE summarizes:

jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. Prior to 4.5.7, JupyterLab's HTML sanitizer allowlists data-commandlinker-command and data-commandlinker-args on button elements, while CommandLinker listens for all click events on document.body and executes the named command without checking whether the element came from trusted JupyterLab UI. A notebook with a pre-saved HTML cell output containing a deceptive button can trigger arbitrary JupyterLab commands - including arbitrary code execution - on a single user click, without any code being submitted for execution by the user. This vulnerability is fixed in 4.5.7.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-42557 since 04/28/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 4.5.7 eliminates this vulnerability.

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Productinfo

Vendor

• Jupyter

Name

• notebook

Version

• 4.5.0
• 4.5.1
• 4.5.2
• 4.5.3
• 4.5.4
• 4.5.5
• 4.5.6

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