CVE-2026-42557

jupyterlab: Command linker attributes in HTML enable one-click command execution from untrusted content

Published May 13, 2026 CVSS 4.0 · 8.6 High EPSS < 1% KEV · Not listed
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

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-mqcg-5x36-vfcg JupyterLab's command linker attributes in HTML enable one-click command execution from untrusted content
History
Type Values Removed Values Added
CPEs cpe:2.3:a:jupyter:jupyterlab:*:*:*:*:*:*:*:*
cpe:2.3:a:jupyter:notebook:*:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 9.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Jupyter
Jupyter jupyterlab
Jupyter notebook
Vendors & Products Jupyter
Jupyter jupyterlab
Jupyter notebook
Type Values Removed Values Added
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.
Title jupyterlab: Command linker attributes in HTML enable one-click command execution from untrusted content
Weaknesses CWE-79
References
Metrics cvssV4_0

{'score': 8.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 28, 2026, 12:04 PM
Reserved
Apr 28, 2026, 4:56 PM
Status
Modified
Published
May 13, 2026, 4:16 PM
Modified
Oct 25, 2026, 11:10 PM