{"cve":"CVE-2026-42557","nvd":{"published":"2026-05-13T16:16:48.167","modified":"2026-10-25T23:10:00.167","status":"Modified","description":"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_v4":{"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","score":8.6},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","score":9.6},"cwes":["CWE-79"],"references":["https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-mqcg-5x36-vfcg","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"],"products":["jupyter:jupyterlab","jupyter:notebook"],"source":"nvd","synced_at":"2026-10-25T23:44:33.281319194+00:00"},"epss":{"cve":"CVE-2026-42557","score":0.00371,"percentile":0.30743,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-mqcg-5x36-vfcg","url":"https://osv.dev/vulnerability/GHSA-mqcg-5x36-vfcg","summary":"JupyterLab's command linker attributes in HTML enable one-click command execution from untrusted content","modified":"2026-09-10T03:51:06.550584406Z","packages":[{"ecosystem":"PyPI","name":"jupyterlab","purl":"pkg:pypi/jupyterlab","ranges":["<4.5.7"],"fixed":["4.5.7"]},{"ecosystem":"PyPI","name":"notebook","purl":"pkg:pypi/notebook","ranges":[">=7.0.0 <7.5.6"],"fixed":["7.5.6"]}]},{"id":"PYSEC-2026-2537","url":"https://osv.dev/vulnerability/PYSEC-2026-2537","summary":"JupyterLab's command linker attributes in HTML enable one-click command execution from untrusted content","modified":"2026-07-13T16:43:04.081738235Z","packages":[{"ecosystem":"PyPI","name":"jupyterlab","purl":"pkg:pypi/jupyterlab","ranges":["<4.5.7"],"fixed":["4.5.7"]}]},{"id":"PYSEC-2026-2681","url":"https://osv.dev/vulnerability/PYSEC-2026-2681","summary":"JupyterLab's command linker attributes in HTML enable one-click command execution from untrusted content","modified":"2026-07-13T16:43:04.081738235Z","packages":[{"ecosystem":"PyPI","name":"notebook","purl":"pkg:pypi/notebook","ranges":[">=7.0.0 <7.5.6"],"fixed":["7.5.6"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}