{"id":"BIT-jupyterlab-2026-42557","summary":"jupyterlab: Command linker attributes in HTML enable one-click command execution from untrusted content","details":"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.","aliases":["BIT-jupyter-base-notebook-2026-42557","BIT-jupyter-notebook-2026-42557","CVE-2026-42557","GHSA-mqcg-5x36-vfcg","PYSEC-2026-2537","PYSEC-2026-2681"],"modified":"2026-09-10T16:01:14.025312020Z","published":"2026-05-15T08:42:30.212Z","database_specific":{"severity":"Critical","cpes":["cpe:2.3:a:jupyter:jupyterlab:*:*:*:*:*:*:*:*"]},"references":[{"type":"ADVISORY","url":"https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-mqcg-5x36-vfcg"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42557"},{"type":"WEB","url":"https://access.redhat.com/security/cve/CVE-2026-42557"},{"type":"WEB","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2477086"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42557.json"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:43038"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:60520"}],"affected":[{"package":{"name":"jupyterlab","ecosystem":"Bitnami","purl":"pkg:bitnami/jupyterlab"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.5.7"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/jupyterlab/BIT-jupyterlab-2026-42557.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H"}]}],"schema_version":"1.9.0"}