{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-35397",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-06T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-08T03:55:36.590Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "jupyter_server",
          "vendor": "jupyter-server",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.18.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 7.6,
            "baseSeverity": "HIGH",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "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",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-05T19:37:33.810Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3"
        }
      ],
      "source": {
        "advisory": "GHSA-5789-5fc7-67v3",
        "discovery": "UNKNOWN"
      },
      "title": "jupyter-server path traversal allows access to sibling directories sharing root_dir name prefix"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-35397",
    "datePublished": "2026-05-05T19:37:33.810Z",
    "dateReserved": "2026-04-02T17:03:42.074Z",
    "dateUpdated": "2026-05-08T03:55:36.590Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.17.0"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "jupyter-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.18.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-35397"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-05T16:49:10Z",
    "nvd_published_at": "2026-05-05T20:16:38Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\nJupyter Server \u003c=2.17.0 can access directories sibling to the root directory, if it starts with the root dir\u0027s name.\n\n### PoC\n\nMinimal:\n\n```\n.\n\u251c\u2500\u2500 test/              \u003c- root directory.\n\u2502   \u2514\u2500\u2500 test.txt\n\u2514\u2500\u2500 testtest/\n    \u2514\u2500\u2500 secret.txt     \u003c- file to exfiltrate that we should not be able to access via API\n```\n\n```bash\nHOST=\"http://localhost:8888\"\nTOKEN=\"\"\nSIBLING=\"testtest\"\nTARGET=\"secret.txt\"\n\ncurl -s -X POST \\\n  \"$HOST/api/contents/%2e%2e/$SIBLING/$TARGET/checkpoints\" \\\n  -H \"Authorization: token $TOKEN\"\n```\n\nFull PoC by @stef41: https://gist.github.com/Yann-P/66d4982a965dee8fcb8dd89db29e7006\n\n### Impact\n\nIt is possible for an authenticated user to access content outside the server\u0027s `root_dir` in siblings directories sharing the same prefix as the `root_dir`. The attacker can escalate access, reading, writing, and deleting from sibling directories.\n\nThis can have a tangible impact for deployments using predictable naming scheme with multi-tenant server, for example `user1`, `user2`, `user3`, ..., `user10` etc, as `user1` could access and modify files of all `user10` - `user19` and higher.\n\nIn a hypothetical system where users can choose a name of their folder, an attacker could choose a single-letter username to gain access to a significant number of sibling directories.\n\n### Workarounds\n\nUse folder names that do not overlap.\n\n### Acknowledgments\n\nThank you to @stef41 for providing a useful PoC.",
  "id": "GHSA-5789-5fc7-67v3",
  "modified": "2026-05-08T15:29:39Z",
  "published": "2026-05-05T16:49:10Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5789-5fc7-67v3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-35397"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jupyter-server/jupyter_server"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Jupyter Server: Path Traversal via incorrect startswith() root directory check allows access to sibling directories"
}