jupyter-server path traversal allows access to sibling directories sharing root_dir name prefix_CVE-2026-35397

{
    "lastseen": "",
    "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. \n\nVersion 2.18.0 contains a fix. As a workaround, ensure folder names do not share a common prefix with any sibling directory.",
    "published": "2026-05-05T19:37:33.810Z",
    "modified": "2026-05-05T19:37:33.810Z",
    "type": "cve",
    "title": "jupyter-server path traversal allows access to sibling directories sharing root_dir name prefix",
    "source": "GitHub_M",
    "references": "https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3",
    "id": "CVE-2026-35397",
    "bulletinFamily": "",
    "cwe": [
        "CWE-22"
    ],
    "cvelist": null,
    "sourceData": "jupyter-server jupyter_server < 2.18.0",
    "sourceHref": "",
    "cvss": {
        "score": 7.6,
        "severity": "HIGH",
        "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",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
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        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "jupyter_server",
    "version": "< 2.18.0",
    "vendor": "jupyter-server",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}