CVE-2026-35397jupyter-server path traversal allows access to sibling directories sharing root_dir name prefix
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.6 HIGH (v4.0, CNA)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
- Weakness (CWE)
- CWE-22
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Modified
- Record last updated
- Aug 28, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
jupyter-server jupyter_server jupyter_server:jupyter_server (from the name) | before 2.18.0 | CNA record |
Red Hat Red Hat Migration Toolkit for Applications 8.2 redhat:migration_toolkit_applications | from 1784109883 not affected | CISA ADP |
Red Hat Red Hat OpenShift AI 3.4 redhat:openshift_ai | from 1787076778 not affected | CISA ADP |
jupyter jupyter_server jupyter:jupyter_server | before 2.18.0 | NVD |
References
- https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3x-refsource-confirm, exploit, vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:43038
- https://access.redhat.com/errata/RHSA-2026:60520
- https://access.redhat.com/security/cve/CVE-2026-35397
- https://bugzilla.redhat.com/show_bug.cgi?id=2466858
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-35397.json
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.