{
  "affected": [
    {
      "affectedData": [
        {
          "product": "jupyterhub",
          "vendor": "jupyterhub",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 4.1.0, \u003c 5.4.5"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:jupyter:jupyterhub:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "81612D2F-7819-4502-B4B1-F9FBFA915A42",
              "versionEndExcluding": "5.4.5",
              "versionStartIncluding": "4.1.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks. In versions 4.1.0 through 5.4.4, XSRF protection (updated in 4.1.0) inappropriately treated requests with Sec-Fetch-Mode: no-cors as same-origin requests, bypassing XSRF checks. The JSON API is not affected, only HTTP form endpoints, such as /hub/spawn and /hub/accept-share, meaning attackers could trigger server spawn (but not access the server) and if the attacker is a JupyterHub user permitted to share access to their server, cause a user to accept a share and have access to the attacker\u0027s server. This issue has been fixed in version 5.4.5. If developers are unable to immediately upgrade, they can temporarily mitigate this issue by dropping requests to JupyterHub with Sec-Fetch-Mode: no-cors if they are using a reverse proxy."
    },
    {
      "lang": "es",
      "value": "JupyterHub es un software que permite a los usuarios crear un servidor multiusuario para notebooks de Jupyter. En las versiones 4.1.0 a 5.4.4, la protecci\u00f3n XSRF (actualizada en 4.1.0) trat\u00f3 de forma inapropiada las solicitudes con Sec-Fetch-Mode: no-cors como solicitudes del mismo origen, eludiendo las comprobaciones XSRF. La API JSON no se ve afectada, solo los puntos finales de formulario HTTP, como /hub/spawn y /hub/accept-share, lo que significa que los atacantes podr\u00edan activar la creaci\u00f3n de un servidor (pero no acceder al servidor) y si el atacante es un usuario de JupyterHub con permiso para compartir el acceso a su servidor, provocar que un usuario acepte un recurso compartido y tenga acceso al servidor del atacante. Este problema ha sido solucionado en la versi\u00f3n 5.4.5. Si los desarrolladores no pueden actualizar de inmediato, pueden mitigar temporalmente este problema descartando las solicitudes a JupyterHub con Sec-Fetch-Mode: no-cors si est\u00e1n utilizando un proxy inverso."
    }
  ],
  "id": "CVE-2026-40864",
  "lastModified": "2026-07-23T11:10:00.120",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 5.4,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 2.5,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 4.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 1.4,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-40864",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-05-26T13:13:45.531785Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-05-22T21:16:43.177",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/jupyterhub/jupyterhub/commit/9c5ec277d3cda5a59de2d8c8117efa77bd941127"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/jupyterhub/jupyterhub/security/advisories/GHSA-m68r-v472-jgq9"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-352"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}