Directory Traversal Affecting jupyter-server package, versions <2.20.0-1


Severity

Recommended
0.0
high
0
10

Snyk's Security Team recommends NVD's CVSS assessment. Learn more

Threat Intelligence

EPSS
0.62% (48th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-DEBIANUNSTABLE-JUPYTERSERVER-16427709
  • published6 May 2026
  • disclosed5 May 2026

Introduced: 5 May 2026

CVE-2026-35397  (opens in a new tab)
CWE-22  (opens in a new tab)

How to fix?

Upgrade Debian:unstable jupyter-server to version 2.20.0-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream jupyter-server package and not the jupyter-server package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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 Base Scores

version 3.1