Critical · published May 13, 2026
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.
| Product | Versions | Fixed in |
|---|---|---|
| jupyter/jupyterlab | < 4.5.7 | 4.5.7 |
| jupyter/notebook | ≥ 7.0.0, < 7.5.6 | 7.5.6 |