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jupyter-server — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2020-26275

The Jupyter Server provides the backend (i.e. the core services, APIs, and REST endpoints) for Jupyter web applications like Jupyter notebook, JupyterLab, and Voila. In Jupyter Server before version 1.1.1, an open redirect vulnerability could cause the jupyter server to redirect the browser to a different malicious website. All jupyter servers running without a base_url prefix are technically affected, however, these maliciously crafted links can only be reasonably made for known jupyter server hosts. A link to your jupyter server may *appear* safe, but ultimately redirect to a spoofed server on the public internet. This same vulnerability was patched in upstream notebook v5.7.8. This is fixed in jupyter_server 1.1.1. If upgrade is not available, a workaround can be to run your server on a url prefix: "jupyter server --ServerApp.base_url=/jupyter/".

Products
jupyter-server
Affected versions
Not specified
Fixed versions
1.1.1-1
CVEs
CVE-2020-26275
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 13:44 UTC · Revision 1

Source evidence

DEBIAN-CVE-2020-26275

core-osv · Original source

Published 21 Dec 2020, 18:15 UTC

The Jupyter Server provides the backend (i.e. the core services, APIs, and REST endpoints) for Jupyter web applications like Jupyter notebook, JupyterLab, and Voila. In Jupyter Server before version 1.1.1, an open redirect vulnerability could cause the jupyter server to redirect the browser to a different malicious website. All jupyter servers running without a base_url prefix are technically affected, however, these maliciously crafted links can only be reasonably made for known jupyter server hosts. A link to your jupyter server may *appear* safe, but ultimately redirect to a spoofed server on the public internet. This same vulnerability was patched in upstream notebook v5.7.8. This is fixed in jupyter_server 1.1.1. If upgrade is not available, a workaround can be to run your server on a url prefix: "jupyter server --ServerApp.base_url=/jupyter/".

osv:DEBIAN-CVE-2020-26275

jupyter-server

Fixed versions: 1.1.1-1

jupyter-server

Fixed versions: 1.1.1-1

jupyter-server

Fixed versions: 1.1.1-1

Complete source record
{
  "id": "b0f25b1a18d2d78f1304e3f0ce064e7c74f4a4f6627e23987266c60d38f9056d",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2020-26275",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2020-26275",
    "summary": "The Jupyter Server provides the backend (i.e. the core services, APIs, and REST endpoints) for Jupyter web applications like Jupyter notebook, JupyterLab, and Voila. In Jupyter Server before version 1.1.1, an open redirect vulnerability could cause the jupyter server to redirect the browser to a different malicious website. All jupyter servers running without a base_url prefix are technically affected, however, these maliciously crafted links can only be reasonably made for known jupyter server hosts. A link to your jupyter server may *appear* safe, but ultimately redirect to a spoofed server on the public internet. This same vulnerability was patched in upstream notebook v5.7.8. This is fixed in jupyter_server 1.1.1. If upgrade is not available, a workaround can be to run your server on a url prefix: \"jupyter server --ServerApp.base_url=/jupyter/\".",
    "evidence": "osv:DEBIAN-CVE-2020-26275",
    "products": [
      {
        "name": {
          "value": "jupyter-server",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.1.1-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "jupyter-server",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.1.1-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "jupyter-server",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.1.1-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2020-26275",
      "aliases": [
        "DEBIAN-CVE-2020-26275"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.1.1-1"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyter-server",
            "purl": "pkg:deb/debian/jupyter-server?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-26275.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.1.1-1"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyter-server",
            "purl": "pkg:deb/debian/jupyter-server?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-26275.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.1.1-1"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyter-server",
            "purl": "pkg:deb/debian/jupyter-server?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-26275.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-26T12:02:40.890152148Z",
      "provider": "osv",
      "upstream": [
        "CVE-2020-26275"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2020-26275"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2020-26275",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 452744,
  "published_at": "2020-12-21T18:15:15.353+00:00"
}