CVE-2026-42266
JupyterLab has an Extension Manager API/GUI Policy Discrepancy allowing 3rd party (malicious) extensions install via POST request.
- State
- Published
- Severity
- 8.8 High
- Published
- May 13, 2026
- Updated
- Aug 28, 2026
- Reserved
- Apr 26, 2026
Description
JupyterLab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 4.0.0 to 4.5.6, the allow-list of extensions that can be installed from PyPI Extension Manager (allowed_extensions_uris) is not correctly enforced by JupyterLab. The PyPI Extension Manager was not contained to packages listed on the default PyPI index. This vulnerability is fixed in 4.5.7.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | GitHub_M |
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | redhat-SADP |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
jupyterlabjupyterlab |
|
References
- https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-37w4-hwhx-4rc4
- https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.7
- https://jupyterhub.readthedocs.io/en/5.2.1/explanation/websecurity.html
- https://jupyterlab.readthedocs.io/en/latest/user/extensions.html#extension-manager-implementations
- https://access.redhat.com/security/cve/CVE-2026-42266vdb-entry
- RHBZ#2477072issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42266.json
- https://access.redhat.com/errata/RHSA-2026:43038vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:60520vendor-advisory
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