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jupyterhub — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2021-41247

JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.

Products
jupyterhub
Affected versions
Not specified
Fixed versions
2.0.0+ds1-1
CVEs
CVE-2021-41247
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 00:44 UTC · Revision 1

Source evidence

DEBIAN-CVE-2021-41247

core-osv · Original source

Published 4 Nov 2021, 18:15 UTC

JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.

osv:DEBIAN-CVE-2021-41247

jupyterhub

Fixed versions: 2.0.0+ds1-1

jupyterhub

Fixed versions: 2.0.0+ds1-1

jupyterhub

Fixed versions: 2.0.0+ds1-1

Complete source record
{
  "id": "7b25f455d9ddb37f799eee1f8670a01a1b791d0f92be01e05cc1a0d69f2939b9",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-41247",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-41247",
    "summary": "JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.",
    "evidence": "osv:DEBIAN-CVE-2021-41247",
    "products": [
      {
        "name": {
          "value": "jupyterhub",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.0.0+ds1-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "jupyterhub",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.0.0+ds1-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "jupyterhub",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.0.0+ds1-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2021-41247",
      "aliases": [
        "DEBIAN-CVE-2021-41247"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.0.0+ds1-1"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyterhub",
            "purl": "pkg:deb/debian/jupyterhub?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-41247.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.0.0+ds1-1"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyterhub",
            "purl": "pkg:deb/debian/jupyterhub?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-41247.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.0.0+ds1-1"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyterhub",
            "purl": "pkg:deb/debian/jupyterhub?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-41247.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-23T18:03:39.256363112Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-41247"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-41247"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-41247",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 422137,
  "published_at": "2021-11-04T18:15:08.707+00:00"
}