High 8.6Published May 13, 2026

CVE-2026-42557jupyterlab: Command linker attributes in HTML enable one-click command execution from untrusted content

Updated under an hour ago (Oct 27, 2026, 11:00 PM ET)

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It affects jupyterlab and 4 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for jupyterlab

Exploited in the last 30 days

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: 8.6 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Modified
Record last updated: Aug 28, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

jupyterlab jupyterlab jupyterlab:jupyterlab (from the name)	before 4.5.7	CNA record
jupyter notebook jupyter:notebook (from the name)	from 7.0.0, < 7.5.6	CNA record
Red Hat Red Hat Migration Toolkit for Applications 8.2 redhat:migration_toolkit_applications	from 1784109883 not affected	CISA ADP
Red Hat Red Hat OpenShift AI 3.4 redhat:openshift_ai	from 1787076778 not affected	CISA ADP
jupyter jupyterlab jupyter:jupyterlab	before 4.5.7	NVD
jupyter notebook jupyter:notebook	from 7.0.0 before 7.5.6	NVD

References

References

https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-mqcg-5x36-vfcg	x-refsource-confirm, 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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.