CVE-2026-67338 jupyterlab CVE debrief

Who should care

Users of JupyterLab versions before 4.5.9, administrators of systems with JupyterLab installed, and security teams monitoring for potential cross-site scripting attacks should be aware of this vulnerability. They should verify their deployments and plan for updates or mitigations as necessary. Additionally, operators and platform administrators should review their configurations and ensure that they are not exposed to this vulnerability. Vulnerability management and security teams should prioritize this issue and conduct thorough reviews of their systems to identify potential exposure. Security teams should also monitor for suspicious activity and implement compensating controls where necessary. Asset inventory and change management processes should be reviewed to ensure that affected systems are properly tracked and remediated. Rollback and change window procedures should be evaluated to minimize potential downtime and ensure smooth remediation. Source tracking and monitoring should be implemented to detect potential exploitation attempts. This vulnerability has a CVSS score of 5.1, indicating a medium level of severity. However, the actual impact may vary depending on the specific use case and deployment scenario. Therefore, it is essential to carefully assess the risk and prioritize remediation efforts accordingly. The CVSS score is based on the CVSS v3.0 scoring system, which provides a standardized way to measure the severity of vulnerabilities. The score takes into account various factors, including the attack vector, attack complexity, privileges required, user interaction, scope, confidentiality impact, integrity impact, and availability impact. In this case, the CVSS score of 5.1 indicates that the vulnerability has a moderate level of severity, but it is still important to prioritize remediation efforts to minimize potential risks. The vulnerability is classified as a stored cross-site scripting (XSS) vulnerability, which can be exploited by attackers to inject malicious code into the application. This type of vulnerability can have significant consequences, including unauthorized access to sensitive data, theft of user credentials, and disruption of业务

Technical 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 project metadata that execute arbitrary JavaScript in the JupyterLab origin when users click the extension name. This vulnerability can be exploited through malicious packages with specially crafted metadata.

Defensive priority

Medium priority given the CVSS score of 5.1 and the potential for stored cross-site scripting attacks.

Recommended defensive actions

• Verify and update JupyterLab to version 4.5.9 or later
• Conduct inventory checks for affected systems
• Implement compensating controls such as input validation and output encoding
• Monitor for suspicious activity and exception tracking
• Review configurations to ensure they are not exposed to this vulnerability
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

Evidence is limited; primary official records indicate a stored cross-site scripting vulnerability in JupyterLab's Extension Manager. Verification tasks are needed to confirm affected scope and inventory checks. Additional verification is required to ensure the accuracy of the information provided.

Official resources