---
id: CVE-2026-42266
title: >-
  JupyterLab is an extensible environment for interactive and reproducible
  computing, based on the Jupyter Notebook Architecture
summary: >-
  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_…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-88
  - CWE-602
vendor: jupyter
product: jupyterlab
affected:
  - 'jupyterlab >= 4.0.0, < 4.5.7'
patched:
  - jupyterlab 4.5.7
published: '2026-05-13'
updated: '2026-07-06'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-42266'
references:
  - url: 'https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.7'
    label: security-advisories@github.com
  - url: >-
      https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-37w4-hwhx-4rc4
    label: security-advisories@github.com
  - url: 'https://jupyterhub.readthedocs.io/en/5.2.1/explanation/websecurity.html'
    label: security-advisories@github.com
  - url: >-
      https://jupyterlab.readthedocs.io/en/latest/user/extensions.html#extension-manager-implementations
    label: security-advisories@github.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-42266'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2477072'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42266.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-42266'
  - url: 'https://github.com/jupyterlab/jupyterlab'
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/jupyterlab/PYSEC-2026-164.yaml
tags:
  - nvd
  - osv
  - pip
epss: 0.00852
epssPercentile: 0.56405
ingestedAt: '2026-07-06T17:44:51.161Z'
aliases:
  - GHSA-37w4-hwhx-4rc4
  - BIT-jupyterlab-2026-42266
  - PYSEC-2026-164
ecosystem: pip
---

## Overview

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

- `jupyterlab >= 4.0.0, < 4.5.7`

## Remediation

Upgrade past the affected range:

- `jupyterlab 4.5.7`

## Package advisory (CVE-2026-42266)

Affected packages:

- `jupyterlab >= 4.0.0, < 4.5.7`

Patched in:

- `jupyterlab 4.5.7`

Source: https://osv.dev/vulnerability/GHSA-37w4-hwhx-4rc4