{"id":"CVE-2026-42266","aliases":["BIT-jupyterlab-2026-42266","GHSA-37w4-hwhx-4rc4","PYSEC-2026-164"],"url":"https://o3.security/vulnerability/CVE-2026-42266","summary":"JupyterLab has an Extension Manager API/GUI Policy Discrepancy allowing 3rd party (malicious) extensions install via POST request.","details":"JupyterLab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 4.0.0 to 4.5.6, the allow-list of extensions that can be installed from PyPI Extension Manager (allowed_extensions_uris) is not correctly enforced by JupyterLab. The PyPI Extension Manager was not contained to packages listed on the default PyPI index. This vulnerability is fixed in 4.5.7.","published":"2026-05-13T15:08:49.846Z","modified":"2026-08-30T03:30:34.088162302Z","cvss":{"score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.00554,"percentile":0.43748,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"jupyterlab","fixedVersion":"4.5.7"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.7"},{"type":"WEB","url":"https://jupyterhub.readthedocs.io/en/5.2.1/explanation/websecurity.html"},{"type":"WEB","url":"https://jupyterlab.readthedocs.io/en/latest/user/extensions.html#extension-manager-implementations"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42266.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:43038"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:60520"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-42266"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42266.json"},{"type":"ADVISORY","url":"https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-37w4-hwhx-4rc4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42266"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2477072"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-30T03:30:34.088162302Z"}}