CVE-2026-5422: Path Traversal in jupyter/jupyter

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 4.9% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-02 · updated 2026-07-22
Weakness: CWE-23

Description

A path traversal vulnerability exists in jupyter-server version 2.17.0 due to an incorrect root directory boundary check in the _get_os_path() function within jupyter_server/services/contents/fileio.py. The check uses startswith(root) without appending a trailing path separator, allowing sibling directories with names starting with the same prefix as root_dir to bypass the check. Additionally, the to_os_path() function in utils.py does not strip ".." from path parts, enabling traversal sequences to bypass the vulnerable check. This vulnerability can lead to unauthorized read/write access to files in sibling directories, potentially exposing sensitive data in shared hosting environments.

Affected products

jupyter-server jupyter_server: 2.17.0

References

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