AI Threat Alert
### Impact A stored Cross-Site Scripting (XSS) vulnerability in Jupyter Notebook allows attackers to steal authentication tokens from users who open malicious notebook files and interact with elements that the attacker can make look indistinguishable from legitimate controls (single click...
Full CISO analysis pending enrichment.
Affected Systems
| Package | Ecosystem | Vulnerable Range | Patched |
|---|---|---|---|
| @jupyter-notebook/help-extension | npm | >= 7.0.0, <= 7.5.5 | 7.5.6 |
| @jupyterlab/help-extension | npm | <= 4.5.6 | 4.5.7 |
| jupyterlab | pip | <= 4.5.6 | 4.5.7 |
| notebook | pip | >= 7.0.0, <= 7.5.5 | 7.5.6 |
Severity & Risk
Recommended Action
Patch available
Update @jupyter-notebook/help-extension to version 7.5.6
Update @jupyterlab/help-extension to version 4.5.7
Update jupyterlab to version 4.5.7
Update notebook to version 7.5.6
Compliance Impact
Compliance analysis pending. Sign in for full compliance mapping when available.
Frequently Asked Questions
What is CVE-2026-40171?
Jupyter Notebook Vulnerable to Authentication Token Theft via CommandLinker XSS
Is CVE-2026-40171 actively exploited?
No confirmed active exploitation of CVE-2026-40171 has been reported, but organizations should still patch proactively.
How to fix CVE-2026-40171?
Update to patched version: @jupyter-notebook/help-extension 7.5.6, @jupyterlab/help-extension 4.5.7, jupyterlab 4.5.7, notebook 7.5.6.
What is the CVSS score for CVE-2026-40171?
No CVSS score has been assigned yet.
Technical Details
NVD Description
### Impact A stored Cross-Site Scripting (XSS) vulnerability in Jupyter Notebook allows attackers to steal authentication tokens from users who open malicious notebook files and interact with elements that the attacker can make look indistinguishable from legitimate controls (single click interaction). The vulnerability enables complete account takeover through the Jupyter REST API, allowing the attacker to: 1. Read all files 2. Modify/create files 3. Access running kernels and execute arbitrary code 4. Create terminals for shell access ### Patches Jupyter Notebook 7.5.6 and JupyterLab 4.5.7 include patches for this vulnerability. ### Workarounds The help extension can be disabled via CLI: ``` jupyter labextension disable @jupyter-notebook/help-extension jupyter labextension disable @jupyterlab/help-extension ``` ### Hardening The patched versions include a toggle to disable the command linker functionality altogether, for example via `overrides.json`: ```json { "@jupyterlab/apputils-extension:sanitizer": { "allowCommandLinker": false } } ``` ### Resources - https://jupyterlab.readthedocs.io/en/latest/user/commands.html#commands-in-markdown-output-and-files ### Acknowledgments Reported by Daniel Teixeira - NVIDIA AI Red Team