CVE-2026-42557
jupyterlab: Command linker attributes in HTML enable one-click command execution from untrusted content
- State
- Published
- Severity
- 8.6 High
- Published
- May 13, 2026
- Updated
- Aug 28, 2026
- Reserved
- Apr 28, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.6 High | 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 | GitHub_M |
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | redhat-SADP |
Weaknesses
- CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Products
| Product | Versions |
|---|---|
jupyterlabjupyterlab |
|
notebookjupyter |
|
References
- https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-mqcg-5x36-vfcg
- https://access.redhat.com/security/cve/CVE-2026-42557vdb-entry
- RHBZ#2477086issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42557.json
- https://access.redhat.com/errata/RHSA-2026:43038vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:60520vendor-advisory
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