CVE-2026-42557
9.6 · CRITICALOverview
CVE-2026-42557 is a critical-severity vulnerability affecting jupyter jupyterlab. It was published on May 13, 2026 and has a CVSS 3.1 base score of 9.6 (CRITICAL).
This vulnerability has a CVSS 3.1 base score of 9.6, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
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.
Remediation
Check the references section for vendor advisories and patches from jupyter. Update jupyterlab to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| jupyter | jupyterlab | >= 0, < 4.5.7 | Affected |
| jupyter | notebook | >= 7.0.0, < 7.5.6 | Affected |
References
Frequently Asked Questions
What is CVE-2026-42557?
CVE-2026-42557 is a critical-severity vulnerability affecting jupyter jupyterlab. It was published on May 13, 2026 and has a CVSS 3.1 base score of 9.6 (CRITICAL).
How severe is CVE-2026-42557?
This vulnerability has a CVSS 3.1 base score of 9.6, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-42557?
Check the references section for vendor advisories and patches from jupyter. Update jupyterlab to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-42557?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-42557 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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