CVE-2026-42266
HIGHjupyterlab: Extension Manager API/GUI Policy Discrepancy allowing 3rd party (malicious) extensions install via POST request.
Title source: cnaDescription
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.
References (7)
Core 7
Core References
Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-42266
Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2477072
X_Refsource_Confirm x_refsource_confirm
https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-37w4-hwhx-4rc4
X_Refsource_Misc x_refsource_misc
https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.7
X_Refsource_Misc x_refsource_misc
https://jupyterhub.readthedocs.io/en/5.2.1/explanation/websecurity.html
X_Refsource_Misc x_refsource_misc
https://jupyterlab.readthedocs.io/en/latest/user/extensions.html#extension-manager-implementations
Scores
CVSS v3
8.8
EPSS
0.0053
EPSS Percentile
41.1%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
total
Details
CWE
CWE-602
CWE-88
Status
published
Products (3)
jupyter/jupyterlab
4.0.0 - 4.5.7
jupyterlab/jupyterlab
>= 4.0.0, < 4.5.7
pypi/jupyterlab
4.0.0 - 4.5.7PyPI
Published
May 13, 2026
Tracked Since
May 13, 2026