VulnerabilityModified

CVE-2026-42266

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.

HIGH 8.8EPSS 5.65%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (5.65%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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 3.1: 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS: 5.65% probability · 93th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Weakness: CWE-88, CWE-602
Affected: jupyter/jupyterlab
Source: security-advisories@github.com

EPSS trend

EPSS moved from 5.7% on 25 October 2026 to 5.7% on 26 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.