Vulnerability in Jupyter Jupyterlab

CVE-2026-42266

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_ex…

EPSS: 0.000 (8.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-42266?
CVE-2026-42266 is a high-severity vulnerability in Jupyter Jupyterlab, classified under Argument Injection. CVSS score: 8.8/10. Published 2026-05-13.
How severe is CVE-2026-42266?
High severity. CVSS v3 base score is 8.8 out of 10.