Insecure Extension Management in JupyterLab by Project Jupyter
CVE-2026-42266

8.8HIGH

Key Information:

Vendor

Jupyterlab

Status
Jupyterlab
Vendor
CVE Published:
13 May 2026

What is CVE-2026-42266?

JupyterLab, an extensible computing environment built on the Jupyter Notebook Architecture, has a vulnerability in versions 4.0.0 to 4.5.6. The allow-list for extensions that can be installed via the PyPI Extension Manager does not enforce restrictions properly, allowing potential installation from unauthorized packages outside the default PyPI index. This flaw was addressed in version 4.5.7, which correctly enforces the allowed extensions, mitigating the risk of malicious extension installations.

Affected Version(s)

jupyterlab >= 4.0.0, < 4.5.7

References

https://github.com/jupyterlab/jupyterlab/security/advisor...
x_refsource_CONFIRM

CVSS V3.1

Score:
8.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.