Review reviewHigh

CVE-2026-42557

jupyterlab jupyterlab, notebook, Red Hat Migration Toolkit for Applications 8.2

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...

CVSS: 8.6
EPSS: 0.35%
CISA KEV: Not listed
Published: 2026.05.14

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.35%

Technical severityCVSS 8.6

Vulnerability overview

Affected product and versions

Product: jupyterlab jupyterlab, notebook, Red Hat Migration Toolkit for Applications 8.2
Affected versions: >= < 4.5.7, >= >= 7.0.0, < 7.5.6, < 4.5.7, >= 7.0.0 < 7.5.6
Fixed versions: 4.5.7, 7.5.6

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that jupyterlab jupyterlab, notebook, Red Hat Migration Toolkit for Applications 8.2 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE: CWE-79