CVE-2026-40171

In Jupyter Notebook versions 7.0.0 through 7.5.5, JupyterLab versions 4.5.6 and earlier, and the corresponding @jupyter-notebook/help-extension and @jupyterlab/help-extension packages before 7.5.6 and 4.5.7, a stored cross-site scripting issue in the help command linker can be chained with attacker-controlled notebook content to steal authentication tokens with a single click. An attacker can craft a malicious notebook file containing elements that appear indistinguishable from legitimate controls and trigger execution when a user interacts with them. Successful exploitation allows theft of the user's authentication token and complete takeover of the Jupyter session through the REST API, including reading files, creating or modifying files, accessing kernels to execute arbitrary code, and creating terminals for shell access. This issue has been fixed in Notebook 7.5.6, JupyterLab 4.5.7, @jupyter-notebook/help-extension 7.5.6, and @jupyterlab/help-extension 4.5.7. As a workaround, disable the affected help extensions or set allowCommandLinker to false in the sanitizer configuration.

CVSS

No CVSS.

References

Link	Resource
https://github.com/jupyter/notebook/security/advisories/GHSA-rch3-82jr-f9w9

Configurations

No configuration.

History

06 May 2026, 20:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-06 20:16

Updated : 2026-06-17 10:44

NVD link : CVE-2026-40171

Mitre link : CVE-2026-40171

CVE.ORG link : CVE-2026-40171

JSON object : View

Products Affected

No product.

CWE

CWE-79

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

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