CVE-2026-67338 PUBLISHED

JupyterLab before 4.5.9 Stored XSS via Extension Manager

Assigner: VulnCheck
Reserved: 29.07.2026 Published: 01.08.2026 Updated: 01.08.2026

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.

CVSS 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
CVSS Score: 5.1

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	Low
Attack Complexity	Low	Integrity	None	Integrity	Low
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	Low
User Interaction	Passive

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS Score: 6.1

Attack Vector	Network	Scope	Changed
Attack Complexity	Low	Confidentiality Impact	Low
Privileges Required	None	Integrity Impact	Low
User Interaction	Required	Availability Impact	None

CVSS 3.1

Product Status

Vendor	jupyterlab
Product	jupyterlab
Versions	Default: unaffected affected from 0 to 4.5.9 (excl.) Version 4.5.9 is unaffected

CVE-2026-67338 PUBLISHED

JupyterLab before 4.5.9 Stored XSS via Extension Manager

Metrics

Product Status

Credits

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Problem Types