jupyter-server — security advisory

{
  "id": "5155f85aeb0adaf0b4a9868495ecbb6f62b7fa2e03cb2a2efc895c6d7de8affc",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-86049",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2026-86049",
    "summary": "Jupyter Server is the backend for Jupyter web applications. Prior to version 2.21.0, the 5xx request logging path in jupyter_server/log.py copies the Referer header into a JSON header block without applying the token scrubbing used for the request URI. A request that returns HTTP 500 while the Referer contains a token-bearing URL can therefore write that token to server logs in plaintext. An attacker who can read those logs can recover the token and use the affected user's Jupyter Server permissions. This issue is fixed in version 2.21.0.",
    "evidence": "osv:UBUNTU-CVE-2026-86049",
    "products": [
      {
        "name": {
          "value": "jupyter-server",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.2.2-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.13.1-1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "jupyter-server",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.23.3-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1.23.3-2",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "jupyter-server",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.17.0-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.20.0-3",
            "evidence": "/affected/2/versions"
          }
        ]
      },
      {
        "name": {
          "value": "jupyter-server",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.15.0-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "2.17.0-1",
            "evidence": "/affected/3/versions"
          }
        ]
      }
    ],
    "severity": "high",
    "structured": {
      "id": "UBUNTU-CVE-2026-86049",
      "aliases": [
        "UBUNTU-CVE-2026-86049"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyter-server",
            "purl": "pkg:deb/ubuntu/jupyter-server?arch=source&distro=jammy",
            "ecosystem": "Ubuntu:22.04:LTS"
          },
          "versions": [
            "1.2.2-1",
            "1.13.1-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86049.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "jupyter-server",
                "binary_version": "1.13.1-1"
              },
              {
                "binary_name": "python3-jupyter-server",
                "binary_version": "1.13.1-1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyter-server",
            "purl": "pkg:deb/ubuntu/jupyter-server?arch=source&distro=noble",
            "ecosystem": "Ubuntu:24.04:LTS"
          },
          "versions": [
            "1.23.3-1",
            "1.23.3-2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86049.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "jupyter-server",
                "binary_version": "1.23.3-2"
              },
              {
                "binary_name": "python3-jupyter-server",
                "binary_version": "1.23.3-2"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyter-server",
            "purl": "pkg:deb/ubuntu/jupyter-server?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "2.17.0-1",
            "2.20.0-3"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86049.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "jupyter-server",
                "binary_version": "2.20.0-3"
              },
              {
                "binary_name": "python3-jupyter-server",
                "binary_version": "2.20.0-3"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyter-server",
            "purl": "pkg:deb/ubuntu/jupyter-server?arch=source&distro=resolute",
            "ecosystem": "Ubuntu:26.04:LTS"
          },
          "versions": [
            "2.15.0-1",
            "2.17.0-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86049.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "jupyter-server",
                "binary_version": "2.17.0-1"
              },
              {
                "binary_name": "python3-jupyter-server",
                "binary_version": "2.17.0-1"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T13:01:13.768149658Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-86049"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-86049",
        "https://www.cve.org/CVERecord?id=CVE-2026-86049",
        "https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-c3mw-737p-c7g2",
        "https://github.com/jupyter-server/jupyter_server/pull/1681",
        "https://github.com/jupyter-server/jupyter_server/commit/52513529af7096e622c00911b17627b266294717",
        "https://github.com/jupyter-server/jupyter_server/releases/tag/v2.21.0"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-86049",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 361323,
  "published_at": "2026-09-17T21:17:00+00:00"
}