jupyterlab: Command linker attributes in HTML enable one-click command execution from untrusted content
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.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-42557US | critical9.6 | — | ||
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 allowlis… | ||||
references
External citations — patches, advisories, analysis.
- https://access.redhat.com/errata/RHSA-2026:43038WEB
- https://access.redhat.com/errata/RHSA-2026:60520WEB
- https://access.redhat.com/security/cve/CVE-2026-42557WEB
- https://bugzilla.redhat.com/show_bug.cgi?id=2477086WEB
- https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-mqcg-5x36-vfcgADVISORY
- https://nvd.nist.gov/vuln/detail/CVE-2026-42557WEB
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42557.jsonWEB
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