CVE-2026-422668.8HighCWE-88

CVE-2026-42266: JupyterLab has an Extension Manager API/GUI Policy Discrepancy allowing 3rd party (malicious) extensions install via POST request.

jupyterlab

Vendor fix available · Affected: jupyterlab · Exploitation: possible (1 to 10%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

5.7%probability of exploitation in the next 30 days

93rd percentile

050100

Higher than 93% of scored CVEs

8.8HighCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

jupyterlab · jupyterlab>= 4.0.0, < 4.5.7

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Possible (1 to 10%). EPSS between 1% and 10%.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Improper Neutralization of Argument Delimiters in a Command · Command and Code Injection
Vendor: jupyterlab
Published: May 2026
Band: Possible (1 to 10%), May 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-42266 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.