{"id":"CVE-2026-35397","title":"Jupyter Server is the backend for Jupyter web applications","summary":"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 whos…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-22"],"vendor":"jupyter","product":"jupyter_server","affected":["jupyter_server < 2.18.0"],"patched":["jupyter_server 2.18.0"],"published":"2026-05-05","updated":"2026-07-22","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-35397","references":[{"url":"https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3","label":"security-advisories@github.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:43038","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/security/cve/CVE-2026-35397","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2466858","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-35397.json","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-35397"},{"url":"https://access.redhat.com/errata/RHSA-2026:60520"},{"url":"https://github.com/jupyter-server/jupyter_server"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/jupyter-server/PYSEC-2026-68.yaml"}],"tags":["nvd","exploit-available","osv","pip"],"epss":0.00622,"epssPercentile":0.48126,"ingestedAt":"2026-07-22T13:03:40.771Z","exploits":{"github":1,"githubRepos":["https://github.com/HiteshGorana/susvibes-jupyter-server-cve-2026-35397"],"checkedAt":"2026-09-21T15:28:47.071Z"},"exploitAvailable":true,"aliases":["GHSA-5789-5fc7-67v3","PYSEC-2026-68"],"ecosystem":"pip","scores":{"nvd":8.8,"osv":7.1},"slug":"CVE-2026-35397","body":"## Overview\n\nJupyter 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. \n\nVersion 2.18.0 contains a fix. As a workaround, ensure folder names do not share a common prefix with any sibling directory.\n\n## Affected\n\n- `jupyter_server < 2.18.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `jupyter_server 2.18.0`\n\n## Package advisory (CVE-2026-35397)\n\nAffected packages:\n\n- `jupyter-server < 2.18.0`\n\nPatched in:\n\n- `jupyter-server 2.18.0`\n\nSource: https://osv.dev/vulnerability/GHSA-5789-5fc7-67v3","depth":"midnight","depthScore":61,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":5136,"id":"CVE-2026-35397","ts":1788887250577,"field":"exploit_available","old":"false","new":"true"},{"seq":4019,"id":"CVE-2026-35397","ts":1788886366423,"field":"exploit_available","old":"true","new":"false"},{"seq":2830,"id":"CVE-2026-35397","ts":1788883033178,"field":"exploit_available","old":"false","new":"true"},{"seq":1859,"id":"CVE-2026-35397","ts":1788882435989,"field":"exploit_available","old":"true","new":"false"},{"seq":957,"id":"CVE-2026-35397","ts":1788881869923,"field":"exploit_available","old":"false","new":"true"}]}