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.

Project Subscriptions

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-5789-5fc7-67v3 Jupyter Server: Path Traversal via incorrect startswith() root directory check allows access to sibling directories
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 05 May 2026 21:45:00 +0000

Type Values Removed Values Added
First Time appeared Jupyter
Jupyter jupyter Server
Vendors & Products Jupyter
Jupyter jupyter Server

Tue, 05 May 2026 20:00:00 +0000

Type Values Removed Values Added
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.
Title jupyter-server path traversal allows access to sibling directories sharing root_dir name prefix
Weaknesses CWE-22
References
Metrics cvssV4_0

{'score': 7.6, 'vector': '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'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-05T19:37:33.810Z

Reserved: 2026-04-02T17:03:42.074Z

Link: CVE-2026-35397

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-05T20:16:38.223

Modified: 2026-05-05T20:16:38.223

Link: CVE-2026-35397

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-05T21:30:05Z

Weaknesses