CVE-2026-35397
Medium
Elevated severity or exploit probability.
CVSS breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
| Attack Vector | N | Network |
| Attack Complexity | L | Low |
| Privileges Required | L | Low |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | H | High |
| Availability | H | High |
Timeline
- 2026-05-05 — Published (NVD)
- 2026-08-28 — Last modified (NVD)
Description
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.
Affected
References
- exploit https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3
- 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
- exploit https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-35397.json