Vulnerability Details CVE-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 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 13.0%
CVSS Severity
CVSS v3 Score 8.8
Products affected by CVE-2026-35397
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cpe:2.3:a:jupyter:jupyter_server:-
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cpe:2.3:a:jupyter:jupyter_server:0.0.1
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cpe:2.3:a:jupyter:jupyter_server:0.0.2
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cpe:2.3:a:jupyter:jupyter_server:0.0.3
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cpe:2.3:a:jupyter:jupyter_server:0.0.4
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cpe:2.3:a:jupyter:jupyter_server:0.0.5
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cpe:2.3:a:jupyter:jupyter_server:0.1.0
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cpe:2.3:a:jupyter:jupyter_server:0.1.1
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cpe:2.3:a:jupyter:jupyter_server:0.2.0
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cpe:2.3:a:jupyter:jupyter_server:0.2.1
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cpe:2.3:a:jupyter:jupyter_server:0.3.0
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cpe:2.3:a:jupyter:jupyter_server:1.0.0
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cpe:2.3:a:jupyter:jupyter_server:1.0.1
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cpe:2.3:a:jupyter:jupyter_server:1.0.2
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cpe:2.3:a:jupyter:jupyter_server:1.0.3
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cpe:2.3:a:jupyter:jupyter_server:1.0.4
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cpe:2.3:a:jupyter:jupyter_server:1.0.5
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cpe:2.3:a:jupyter:jupyter_server:1.0.6
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cpe:2.3:a:jupyter:jupyter_server:1.0.7
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cpe:2.3:a:jupyter:jupyter_server:1.1.1
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cpe:2.3:a:jupyter:jupyter_server:1.10.0
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cpe:2.3:a:jupyter:jupyter_server:1.10.1
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cpe:2.3:a:jupyter:jupyter_server:1.10.2
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cpe:2.3:a:jupyter:jupyter_server:1.11.0
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cpe:2.3:a:jupyter:jupyter_server:1.11.1
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cpe:2.3:a:jupyter:jupyter_server:1.11.2
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cpe:2.3:a:jupyter:jupyter_server:1.12.0
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cpe:2.3:a:jupyter:jupyter_server:1.12.1
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cpe:2.3:a:jupyter:jupyter_server:1.13.0
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cpe:2.3:a:jupyter:jupyter_server:1.13.1
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cpe:2.3:a:jupyter:jupyter_server:1.13.2
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cpe:2.3:a:jupyter:jupyter_server:1.13.3
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cpe:2.3:a:jupyter:jupyter_server:1.13.4
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cpe:2.3:a:jupyter:jupyter_server:1.13.5
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cpe:2.3:a:jupyter:jupyter_server:1.15.0
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cpe:2.3:a:jupyter:jupyter_server:1.15.1
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cpe:2.3:a:jupyter:jupyter_server:1.15.2
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cpe:2.3:a:jupyter:jupyter_server:1.15.3
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cpe:2.3:a:jupyter:jupyter_server:1.15.4
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cpe:2.3:a:jupyter:jupyter_server:1.15.5
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cpe:2.3:a:jupyter:jupyter_server:1.15.6
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cpe:2.3:a:jupyter:jupyter_server:1.16.0
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cpe:2.3:a:jupyter:jupyter_server:1.17.0
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cpe:2.3:a:jupyter:jupyter_server:1.17.1
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cpe:2.3:a:jupyter:jupyter_server:1.18.0
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cpe:2.3:a:jupyter:jupyter_server:1.18.1
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cpe:2.3:a:jupyter:jupyter_server:1.19.0
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cpe:2.3:a:jupyter:jupyter_server:1.19.1
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cpe:2.3:a:jupyter:jupyter_server:1.21.0
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cpe:2.3:a:jupyter:jupyter_server:1.23.0
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cpe:2.3:a:jupyter:jupyter_server:1.23.1
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cpe:2.3:a:jupyter:jupyter_server:1.23.2
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cpe:2.3:a:jupyter:jupyter_server:1.23.3
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cpe:2.3:a:jupyter:jupyter_server:1.23.4
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cpe:2.3:a:jupyter:jupyter_server:1.23.5
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cpe:2.3:a:jupyter:jupyter_server:1.23.6
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cpe:2.3:a:jupyter:jupyter_server:1.24.0
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cpe:2.3:a:jupyter:jupyter_server:1.6.2
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cpe:2.3:a:jupyter:jupyter_server:1.6.3
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cpe:2.3:a:jupyter:jupyter_server:1.6.4
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cpe:2.3:a:jupyter:jupyter_server:1.7.0
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cpe:2.3:a:jupyter:jupyter_server:1.8.0
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cpe:2.3:a:jupyter:jupyter_server:1.9.0
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cpe:2.3:a:jupyter:jupyter_server:2.0.0
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cpe:2.3:a:jupyter:jupyter_server:2.0.1
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cpe:2.3:a:jupyter:jupyter_server:2.0.2
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cpe:2.3:a:jupyter:jupyter_server:2.0.3
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cpe:2.3:a:jupyter:jupyter_server:2.0.4
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cpe:2.3:a:jupyter:jupyter_server:2.0.5
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cpe:2.3:a:jupyter:jupyter_server:2.0.6
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cpe:2.3:a:jupyter:jupyter_server:2.0.7
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cpe:2.3:a:jupyter:jupyter_server:2.1.0
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cpe:2.3:a:jupyter:jupyter_server:2.10.0
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cpe:2.3:a:jupyter:jupyter_server:2.10.1
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cpe:2.3:a:jupyter:jupyter_server:2.11.0
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cpe:2.3:a:jupyter:jupyter_server:2.11.1
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cpe:2.3:a:jupyter:jupyter_server:2.11.2
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cpe:2.3:a:jupyter:jupyter_server:2.12.0
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cpe:2.3:a:jupyter:jupyter_server:2.12.1
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cpe:2.3:a:jupyter:jupyter_server:2.12.2
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cpe:2.3:a:jupyter:jupyter_server:2.12.3
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cpe:2.3:a:jupyter:jupyter_server:2.12.4
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cpe:2.3:a:jupyter:jupyter_server:2.12.5
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cpe:2.3:a:jupyter:jupyter_server:2.13.0
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cpe:2.3:a:jupyter:jupyter_server:2.14.0
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cpe:2.3:a:jupyter:jupyter_server:2.14.1
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cpe:2.3:a:jupyter:jupyter_server:2.14.2
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cpe:2.3:a:jupyter:jupyter_server:2.15.0
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cpe:2.3:a:jupyter:jupyter_server:2.16.0
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cpe:2.3:a:jupyter:jupyter_server:2.17.0
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cpe:2.3:a:jupyter:jupyter_server:2.2.0
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cpe:2.3:a:jupyter:jupyter_server:2.2.1
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cpe:2.3:a:jupyter:jupyter_server:2.3.0
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cpe:2.3:a:jupyter:jupyter_server:2.4.0
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cpe:2.3:a:jupyter:jupyter_server:2.5.0
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cpe:2.3:a:jupyter:jupyter_server:2.6.0
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cpe:2.3:a:jupyter:jupyter_server:2.7.0
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cpe:2.3:a:jupyter:jupyter_server:2.7.1
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cpe:2.3:a:jupyter:jupyter_server:2.7.2
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cpe:2.3:a:jupyter:jupyter_server:2.7.3
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cpe:2.3:a:jupyter:jupyter_server:2.8.0
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cpe:2.3:a:jupyter:jupyter_server:2.9.0
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cpe:2.3:a:jupyter:jupyter_server:2.9.1