CVE-2026-42557

jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. Prior to 4.5.7, JupyterLab's HTML sanitizer allowlists data-commandlinker-command and data-commandlinker-args on button elements, while CommandLinker listens for all click events on document.body and executes the named command without checking whether the element came from trusted JupyterLab UI. A notebook with a pre-saved HTML cell output containing a deceptive button can trigger arbitrary JupyterLab commands - including arbitrary code execution - on a single user click, without any code being submitted for execution by the user. This vulnerability is fixed in 4.5.7.

CVSS v3 9.6 CRITICAL

9.6^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 2.8 / Impact : 6.0

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope CHANGED

References

Link	Resource
https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-mqcg-5x36-vfcg	Mitigation Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:43038
https://access.redhat.com/errata/RHSA-2026:60520
https://access.redhat.com/security/cve/CVE-2026-42557
https://bugzilla.redhat.com/show_bug.cgi?id=2477086
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42557.json

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:jupyter:jupyterlab::::::::
	cpe:2.3:a:jupyter:notebook::::::::

History

No history.

Information

Published : 2026-05-13 16:16

Updated : 2026-08-28 16:18

NVD link : CVE-2026-42557

Mitre link : CVE-2026-42557

CVE.ORG link : CVE-2026-42557

JSON object : View

Products Affected

jupyter

jupyterlab
notebook

CWE

CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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