{"id":"UBUNTU-CVE-2026-73626","details":"JupyterLab versions \u003e=4.6.0,\u003c=4.6.1 and \u003c=4.5.9 contain an allowlist/blocklist enforcement gap in PyPIExtensionManager.install(). A missing 'await' caused the is_install_allowed coroutine to never execute, so the extension allowlist/blocklist check was not enforced for direct callers of install(). The stock JupyterLab HTTP API and Extension Manager UI are not affected, as they perform a separate, correctly awaited check. The issue affects only deployments where a custom extension or downstream integration imports PyPIExtensionManager and calls install() directly with a package name influenced by untrusted input, an allowlist/blocklist is configured, the PyPI Extension Manager is enabled, and kernels and terminals are disabled or delegated to remote hosts. Fixed in JupyterLab 4.6.2 and 4.5.10.","modified":"2026-08-31T17:16:59.785194500Z","published":"2026-08-13T12:17:00Z","upstream":["CVE-2026-73626"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-73626"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-73626"},{"type":"REPORT","url":"https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-whvh-wf3x-g77j"},{"type":"REPORT","url":"https://www.vulncheck.com/advisories/jupyterlab-before-authentication-bypass-via-pypiextensionmanager"}],"affected":[{"package":{"name":"jupyterlab","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/jupyterlab?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.11+ds1+~cs11.25.27-7","4.0.11+ds1+~cs11.25.27-8","4.0.11+ds1+~cs11.25.27-9"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyterlab","binary_version":"4.0.11+ds1+~cs11.25.27-9"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73626.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}