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BREW-JUPYTERLAB-CVE-2026-5422 (PYSEC-2026-2532)

Vulnerability from osv_homebrew – Published: 2026-08-13 17:01 – Updated: 2026-09-17 19:02 – Source website
VLAI
Summary
Jupyter Server vulnerable to Path Traversal via incorrect root directory boundary check in _get_os_path()
Details

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.

Severity
6.8 (Medium)
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "resource": "jupyter-server",
        "resource_purl": "pkg:pypi/jupyter-server@2.21.0",
        "upstream_fixed_in": "2.18.2"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "jupyterlab",
        "purl": "pkg:brew/jupyterlab"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "4.5.7_2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/jupyter-server@2.21.0",
        "name": "jupyter-server",
        "resource": "jupyter-server",
        "strategy": "registry",
        "subject_version": "2.21.0"
      }
    ]
  },
  "details": "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.",
  "id": "BREW-jupyterlab-CVE-2026-5422",
  "modified": "2026-09-17T19:02:18Z",
  "published": "2026-08-13T17:01:18Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-5422"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jupyter-server/jupyter_server"
    },
    {
      "type": "WEB",
      "url": "https://huntr.com/bounties/24a36953-6490-466f-8cb2-a90d1ca56e0f"
    },
    {
      "type": "WEB",
      "url": "http://github.com/jupyter-server/jupyter_server/commit/0d829f2c35a481c3b24ecbe1e25a6f79954e88f2"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/jupyter-server"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-gf7q-q4j7-hp7c"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Jupyter Server vulnerable to Path Traversal via incorrect root directory boundary check in _get_os_path() ",
  "upstream": [
    "PYSEC-2026-2532",
    "CVE-2026-5422",
    "GHSA-gf7q-q4j7-hp7c"
  ]
}



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