jupyterhub — security advisory

{
  "id": "9b9cb35e9833ca18a3de0f5009f844e7d7f8ae126865cfd27a5eb377a4dd4da7",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-108752",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2026-108752",
    "summary": "JupyterHub through 6.0.1 contains an identifier collision vulnerability that allows authenticated users to overwrite another user's named-server OAuth client by registering a hyphenated username. Attackers holding a name like alice-prod can overwrite the client for alice's server prod, breaking OAuth login and revoking tokens by stopping their own server.",
    "evidence": "osv:UBUNTU-CVE-2026-108752",
    "products": [
      {
        "name": {
          "value": "jupyterhub",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.0.0+ds1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.0.0+ds1-2",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "jupyterhub",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "3.0.0+ds1-1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "jupyterhub",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "5.2.1+ds1-4",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "5.2.1+ds1-5",
            "evidence": "/affected/2/versions"
          }
        ]
      },
      {
        "name": {
          "value": "jupyterhub",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "5.2.1+ds1-4",
            "evidence": "/affected/3/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "UBUNTU-CVE-2026-108752",
      "aliases": [
        "UBUNTU-CVE-2026-108752"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L"
        },
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyterhub",
            "purl": "pkg:deb/ubuntu/jupyterhub?arch=source&distro=jammy",
            "ecosystem": "Ubuntu:22.04:LTS"
          },
          "versions": [
            "2.0.0+ds1-1",
            "2.0.0+ds1-2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-108752.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "jupyterhub",
                "binary_version": "2.0.0+ds1-2"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyterhub",
            "purl": "pkg:deb/ubuntu/jupyterhub?arch=source&distro=noble",
            "ecosystem": "Ubuntu:24.04:LTS"
          },
          "versions": [
            "3.0.0+ds1-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-108752.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "jupyterhub",
                "binary_version": "3.0.0+ds1-1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyterhub",
            "purl": "pkg:deb/ubuntu/jupyterhub?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "5.2.1+ds1-4",
            "5.2.1+ds1-5"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-108752.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "jupyterhub",
                "binary_version": "5.2.1+ds1-5"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyterhub",
            "purl": "pkg:deb/ubuntu/jupyterhub?arch=source&distro=resolute",
            "ecosystem": "Ubuntu:26.04:LTS"
          },
          "versions": [
            "5.2.1+ds1-4"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-108752.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "jupyterhub",
                "binary_version": "5.2.1+ds1-4"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T12:59:48.852595519Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-108752"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-108752",
        "https://www.cve.org/CVERecord?id=CVE-2026-108752",
        "https://github.com/jupyterhub/jupyterhub",
        "https://github.com/jupyterhub/jupyterhub/blob/3e516c6f382b481e815ec455befb2f14d80d337b/jupyterhub/oauth/provider.py#L719-L754",
        "https://github.com/jupyterhub/jupyterhub/blob/3e516c6f382b481e815ec455befb2f14d80d337b/jupyterhub/user.py#L1174-L1186",
        "https://github.com/jupyterhub/jupyterhub/blob/3e516c6f382b481e815ec455befb2f14d80d337b/jupyterhub/user.py#L563-L567",
        "https://hackmd.io/@haind/jupyterhub-oauth-client-id-cross-user-collision",
        "https://www.vulncheck.com/advisories/jupyterhub-through-6.0.1-oauth-client-id-collision-via-unescaped-hyphen"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-108752",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 359800,
  "published_at": "2026-10-11T13:17:00+00:00"
}