by Kastro
Paper/Archive/CVE-2026-42557

CVE-2026-42557

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

EPSS 0.4%CVSS 9.6
critical.is priorityof 100
35
CVSS 9.6 (NVD)9.6 / 10 × 3028.8Not in CISA KEV+300.0EPSS percentile 31.0.310 × 206.2No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
jupyterlab< 4.5.7–CNA
notebook>= 7.0.0, < 7.5.6–CNA
Red Hat Migration Toolkit for Applications 8.2see advisory1784109883redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787076778redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787077779redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787076481redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787074331redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787073913redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787074078redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787073929redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787073605redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787073546redhat-SADP

Scores by source

NVD9.6CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
redhat-SADP (CNA)8.8CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
GitHub_M (CNA)8.6CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

refgithub.com/jupyterlab/jupyterlab/security/advisories/GHSA-mqcg-5x36-vfcgrefaccess.redhat.com/security/cve/CVE-2026-42557refbugzilla.redhat.com/show_bug.cgi?id=2477086refsecurity.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42557.jsonadvisoryaccess.redhat.com/errata/RHSA-2026:43038advisoryaccess.redhat.com/errata/RHSA-2026:60520