{"id":"CVE-2026-5422","aliases":["GHSA-gf7q-q4j7-hp7c"],"title":"Jupyter Server vulnerable to Path Traversal via incorrect root directory boundary check in _get_os_path() ","summary":"Jupyter Server vulnerable to Path Traversal via incorrect root directory boundary check in _get_os_path() ","severity":"medium","cvss":6.8,"cvssVector":"CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","vendor":"jupyter-server","product":"jupyter-server","ecosystem":"pip","affected":["jupyter-server < 2.18.2"],"patched":["jupyter-server 2.18.2"],"published":"2026-06-02","updated":"2026-07-09","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-gf7q-q4j7-hp7c","references":[{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-5422"},{"url":"https://github.com/jupyter-server/jupyter_server"},{"url":"https://huntr.com/bounties/24a36953-6490-466f-8cb2-a90d1ca56e0f"},{"url":"http://github.com/jupyter-server/jupyter_server/commit/0d829f2c35a481c3b24ecbe1e25a6f79954e88f2"}],"tags":["osv","pip"],"epss":0.00437,"epssPercentile":0.37459,"ingestedAt":"2026-07-10T13:49:10.786Z","slug":"CVE-2026-5422","body":"## Overview\n\nA path traversal vulnerability exists in jupyter-server version 2.17.0 due to an incorrect root directory boundary check in the _get_os_path() function within jupyter_server/services/contents/fileio.py. The check uses startswith(root) without appending a trailing path separator, allowing sibling directories with names starting with the same prefix as root_dir to bypass the check. Additionally, the to_os_path() function in utils.py does not strip \"..\" from path parts, enabling traversal sequences to bypass the vulnerable check. This vulnerability can lead to unauthorized read/write access to files in sibling directories, potentially exposing sensitive data in shared hosting environments.\n\n## Affected packages\n\n- `jupyter-server < 2.18.2`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `jupyter-server 2.18.2`","depth":"sunlit","depthScore":37,"depthScoreParts":{"impact":37.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}