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CVE-2026-42266

JupyterLab has an Extension Manager API/GUI Policy Discrepancy allowing 3rd party (malicious) extensions install via POST request.

Published: May 13, 2026Updated: May 26, 2026 Sources: CVE List NVDCWE-88
NVD MITRE
8.8CVSSHIGH
EPSS Score
0.5%
Top 62.0%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-88CWE-602

Affected Products

jupyterlabjupyterlab
On-prem
DevTools & CI / ide-editor
jupyterlabjupyter
Mixed
AI / ML / notebook-mlops
jupyterlaboss-projectDevTools & CIaka jupyter lab
jupyteross-projectAI / MLaka notebook, jupyter server, jupyterlab

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available
Workaround Available

MITRE ATT&CK

1 technique
Execution
View detailed technique mapping

References

https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-37w4-hwhx-4rc4
github.com
https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.7
github.com
https://jupyterhub.readthedocs.io/en/5.2.1/explanation/websecurity.html
jupyterhub.readthedocs.io
and 1 more references View all →

Timeline

Published
May 13, 2026
Last Updated
May 26, 2026

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