UBUNTU-CVE-2026-108752 (CVE-2026-108752)

Vulnerability from osv_ubuntu – Published: 2026-10-13 00:00 – Updated: 2026-10-13 00:00 – Source website
VLAI
Details

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.

Severity
4.2 (Medium)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L
2.3 (Low)
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
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jupyterhub",
            "binary_version": "2.0.0+ds1-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "jupyterhub",
        "purl": "pkg:deb/ubuntu/jupyterhub@2.0.0+ds1-2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.0+ds1-1",
        "2.0.0+ds1-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jupyterhub",
            "binary_version": "3.0.0+ds1-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "jupyterhub",
        "purl": "pkg:deb/ubuntu/jupyterhub@3.0.0+ds1-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.0+ds1-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jupyterhub",
            "binary_version": "5.2.1+ds1-4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "jupyterhub",
        "purl": "pkg:deb/ubuntu/jupyterhub@5.2.1+ds1-4?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.2.1+ds1-4"
      ]
    }
  ],
  "aliases": [],
  "details": "JupyterHub through 6.0.1 contains an identifier collision vulnerability that allows authenticated users to overwrite another user\u0027s named-server OAuth client by registering a hyphenated username. Attackers holding a name like alice-prod can overwrite the client for alice\u0027s server prod, breaking OAuth login and revoking tokens by stopping their own server.",
  "id": "UBUNTU-CVE-2026-108752",
  "modified": "2026-10-13T00:00:00Z",
  "published": "2026-10-13T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-108752"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-108752"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/jupyterhub/jupyterhub"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/jupyterhub/jupyterhub/blob/3e516c6f382b481e815ec455befb2f14d80d337b/jupyterhub/oauth/provider.py#L719-L754"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/jupyterhub/jupyterhub/blob/3e516c6f382b481e815ec455befb2f14d80d337b/jupyterhub/user.py#L1174-L1186"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/jupyterhub/jupyterhub/blob/3e516c6f382b481e815ec455befb2f14d80d337b/jupyterhub/user.py#L563-L567"
    },
    {
      "type": "REPORT",
      "url": "https://hackmd.io/@haind/jupyterhub-oauth-client-id-cross-user-collision"
    },
    {
      "type": "REPORT",
      "url": "https://www.vulncheck.com/advisories/jupyterhub-through-6.0.1-oauth-client-id-collision-via-unescaped-hyphen"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L",
      "type": "CVSS_V3"
    },
    {
      "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": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-108752"
  ]
}



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