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.

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction Passive

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact Low

Subsequent System Integrity Impact Low

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
jupyterlab jupyterlab unaffected
Version Status Constraints
0 affected < 4.5.9
4.5.9 unaffected —

No data.

No data.

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Vendors Products
Jupyter Subscribe
Jupyterlab Subscribe

Project Subscriptions

Vendors Products
Jupyter Subscribe
Jupyterlab Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/jupyterlab/jupyterlab/commit/4e61e07d0a91145b53fbf96ac74b0387f6bc51f6 cve-icon
https://github.com/jupyterlab/jupyterlab/commit/d5d961f6e10a6442dddbf94d9a976b3897055a12 cve-icon
https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-vmhf-c436-hxj4 cve-icon
https://www.vulncheck.com/advisories/jupyterlab-before-stored-xss-via-extension-manager cve-icon
History

Sat, 01 Aug 2026 12:45:00 +0000

Type Values Removed Values Added
Description 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.
Title JupyterLab before 4.5.9 Stored XSS via Extension Manager
First Time appeared Jupyter
Jupyter jupyterlab
Weaknesses CWE-84
CPEs cpe:2.3:a:jupyter:jupyterlab:*:*:*:*:*:*:*:*
Vendors & Products Jupyter
Jupyter jupyterlab
References
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-01T12:22:17.437Z

Reserved: 2026-07-29T13:09:45.992Z

Link: CVE-2026-67338

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-01T15:00:06Z

Weaknesses