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Vulnerabilities

Vulnerability · CVE-2026-35397

Jupyter Server is the backend for Jupyter web applications.

Published May 5, 2026 · catalog updated Aug 28, 2026 · jupyter server

Check if you run it

No confirmed exploitation is on record for CVE-2026-35397. EPSS is 0.67%. Act only if a listed version of jupyter server is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.6
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.67%
Remediation
Version ranges on file
Affected products
cpe jupyter/jupyter server · stated jupyter server

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe jupyter/jupyter serverversion unspecified
  • stated jupyter server<= 2.17.0

How to fix CVE-2026-35397

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-35397. EPSS is 0.67%. Act only if a listed version of jupyter server is installed.

Which versions are affected?

Compare what you have installed with jupyter server <= 2.17.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-22: Path Traversal. EPSS 0.67%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. May 5, 2026 · NIST NVD

    Detected

    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" throu

  2. Aug 28, 2026 · NIST NVD

    Updated

    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" throu

Sources

  • CVE.orgVulnerability recordCVE-2026-35397

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-35397

    30-day exploitation probability 0.7%

    first.org
  • NIST NVDVulnerability recordCVE-2026-35397

    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 r

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.