{"id":"UBUNTU-CVE-2026-35397","details":"Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, a path traversal vulnerability in the REST API allows an authenticated user to escape the configured root_dir and access sibling directories whose names begin with the same prefix as the root_dir. For example, with a root_dir named \"test\", the API permits access to a sibling directory named \"testtest\" through a crafted request to the /api/contents endpoint using encoded path components. An attacker can read, write, and delete files in affected sibling directories. Multi-tenant deployments using predictable naming schemes are particularly at risk, as a user with a directory named \"user1\" could access directories for user10 through user19 and beyond. A user who can choose a single-character folder name could gain access to a significant number of sibling directories. Version 2.18.0 contains a fix. As a workaround, ensure folder names do not share a common prefix with any sibling directory.","modified":"2026-06-30T18:17:58.658788241Z","published":"2026-05-05T20:16:00Z","upstream":["CVE-2026-35397"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-35397"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-35397"},{"type":"REPORT","url":"https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3"}],"affected":[{"package":{"name":"jupyter-server","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/jupyter-server?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.2-1","1.13.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyter-server","binary_version":"1.13.1-1"},{"binary_name":"python3-jupyter-server","binary_version":"1.13.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-35397.json"}},{"package":{"name":"jupyter-server","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/jupyter-server?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.23.3-1","1.23.3-2"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyter-server","binary_version":"1.23.3-2"},{"binary_name":"python3-jupyter-server","binary_version":"1.23.3-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-35397.json"}},{"package":{"name":"jupyter-server","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/jupyter-server?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.14.2-5","2.15.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyter-server","binary_version":"2.15.0-1"},{"binary_version":"2.15.0-1","binary_name":"python3-jupyter-server"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-35397.json"}},{"package":{"name":"jupyter-server","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/jupyter-server?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.15.0-1","2.17.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyter-server","binary_version":"2.17.0-1"},{"binary_version":"2.17.0-1","binary_name":"python3-jupyter-server"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-35397.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}