CVE-2026-40171

jupyterlab: In Jupyter Notebook versions 7.0.0 through 7.5.5, JupyterLab versions 4.5.6 and earlier, and the corresponding @jupyt...

CVE-2026-40171 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-40171, released May 6, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
n/a
No vendor severity
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0048
41st percentile

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.

Where it's fixed

ProductFixed inFixReleased
Linux
jupyter-notebook · Debian 14 7.4.7-3 DEBIAN-CVE-2026-40171 May 6, 2026
jupyterlab · Debian 14 4.4.10+ds1+~3.1.0+~0.16.6+~cs1.4.4-3 DEBIAN-CVE-2026-40171 May 6, 2026

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