JupyterHub through 6.0.1 OAuth Client ID Collision via Unescaped Hyphen

{
  "id": "a0a45472be9fa51a23f6c55f2a4fc1073d2658dd4fb93b6716bc02940b7bbda0",
  "url": "https://osv.dev/vulnerability/BIT-jupyterhub-2026-108752",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "JupyterHub through 6.0.1 OAuth Client ID Collision via Unescaped Hyphen",
    "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:BIT-jupyterhub-2026-108752",
    "products": [
      {
        "name": {
          "value": "jupyterhub",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.0",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "BIT-jupyterhub-2026-108752",
      "aliases": [
        "BIT-jupyterhub-2026-108752",
        "CVE-2026-108752"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "6.1.0"
                }
              ]
            }
          ],
          "package": {
            "name": "jupyterhub",
            "purl": "pkg:bitnami/jupyterhub",
            "ecosystem": "Bitnami"
          },
          "severity": [
            {
              "type": "CVSS_V3",
              "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L"
            }
          ],
          "database_specific": {
            "source": "https://github.com/bitnami/vulndb/tree/main/data/jupyterhub/BIT-jupyterhub-2026-108752.json"
          }
        }
      ],
      "modified": "2026-10-16T09:45:25.604844190Z",
      "provider": "osv",
      "references": [
        "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://nvd.nist.gov/vuln/detail/CVE-2026-108752",
        "https://www.vulncheck.com/advisories/jupyterhub-through-6.0.1-oauth-client-id-collision-via-unescaped-hyphen"
      ],
      "provider_metadata": {
        "cpes": [
          "cpe:2.3:a:jupyter:jupyterhub:*:*:*:*:*:python:*:*"
        ],
        "severity": "Medium"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-108752",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 338446,
  "published_at": "2026-10-16T08:38:05.91+00:00"
}