---
id: CVE-2026-67338
title: >-
  JupyterLab before 4.5.9 contains a stored cross-site scripting vulnerability
  in the Extension Manager that fails to validate URI protocols in package
  metadata URLs
summary: >-
  JupyterLab before 4.5.9 contains a stored cross-site scripting vulnerability
  in the Extension Manager that fails to validate URI protocols in package
  metadata URLs. Attackers can publish malicious PyPI packages with javascript:
  URLs in p…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'
cwe:
  - CWE-84
published: '2026-08-01'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T20:36:38.867'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-67338'
references:
  - url: >-
      https://github.com/jupyterlab/jupyterlab/commit/4e61e07d0a91145b53fbf96ac74b0387f6bc51f6
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/jupyterlab/jupyterlab/commit/d5d961f6e10a6442dddbf94d9a976b3897055a12
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-vmhf-c436-hxj4
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/jupyterlab-before-stored-xss-via-extension-manager
    label: disclosure@vulncheck.com
  - url: 'https://github.com/jupyterlab/jupyterlab'
  - url: 'https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.9'
tags:
  - nvd
  - osv
  - pip
epss: 0.00172
epssPercentile: 0.06948
ingestedAt: '2026-08-02T09:18:11.534Z'
aliases:
  - GHSA-vmhf-c436-hxj4
ecosystem: pip
vendor: jupyterlab
product: jupyterlab
affected:
  - jupyterlab < 4.5.9
patched:
  - jupyterlab 4.5.9
---

## Overview

JupyterLab before 4.5.9 contains a stored cross-site scripting vulnerability in the Extension Manager that fails to validate URI protocols in package metadata URLs. Attackers can publish malicious PyPI packages with javascript: URLs in project metadata that execute arbitrary JavaScript in the JupyterLab origin when users click the extension name.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-67338)

Affected packages:

- `jupyterlab < 4.5.9`

Patched in:

- `jupyterlab 4.5.9`

Source: https://osv.dev/vulnerability/GHSA-vmhf-c436-hxj4