Vulnerability-Lookup

GHSA-M68R-V472-JGQ9

Vulnerability from github – Published: 2026-05-05 18:10 – Updated: 2026-05-05 18:10

Summary

JupyterHub has cross-origin form POSTs bypass XSRF (CWE-352)

Details

Summary

JupyterHub's XSRF protection (updated in 4.1.0) inappropriately treated requests with Sec-Fetch-Mode: no-cors as same-origin requests, which they are not, 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's server.

Patches

Upgrade to JupyterHub 5.4.5.

Mitigations

If a reverse proxy is in use, drop requests to JupyterHub with Sec-Fetch-Mode: no-cors.

Severity

5.4 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L

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JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "jupyterhub"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.1.0"
            },
            {
              "fixed": "5.4.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40864"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-352"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-05T18:10:58Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nJupyterHub\u0027s XSRF protection (updated in 4.1.0) inappropriately treated requests with `Sec-Fetch-Mode: no-cors` as same-origin requests, which they are not, 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.\n\n## Patches\n\nUpgrade to JupyterHub 5.4.5.\n\n## Mitigations\n\nIf a reverse proxy is in use, drop requests to JupyterHub with `Sec-Fetch-Mode: no-cors`.",
  "id": "GHSA-m68r-v472-jgq9",
  "modified": "2026-05-05T18:10:58Z",
  "published": "2026-05-05T18:10:58Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/jupyterhub/jupyterhub/security/advisories/GHSA-m68r-v472-jgq9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jupyterhub/jupyterhub"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "JupyterHub has cross-origin form POSTs bypass XSRF (CWE-352)"
}

CVE-2026-40864 (GCVE-0-2026-40864)

Vulnerability from cvelistv5 – Published: 2026-05-22 20:13 – Updated: 2026-05-26 13:13

Title

JupyterHub: Cross-origin form POSTs bypass XSRF

Summary

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's 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.

Severity

5.4 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L

CWE

CWE-352 - Cross-Site Request Forgery (CSRF)

Assigner

GitHub_M

References

2 references

URL	Tags
https://github.com/jupyterhub/jupyterhub/security…	x_refsource_CONFIRM
https://github.com/jupyterhub/jupyterhub/commit/9…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
jupyterhub	jupyterhub	Affected: >= 4.1.0, < 5.4.5

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-40864",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-26T13:13:45.531785Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-26T13:13:51.723Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "jupyterhub",
          "vendor": "jupyterhub",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 4.1.0, \u003c 5.4.5"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "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"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-352",
              "description": "CWE-352: Cross-Site Request Forgery (CSRF)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-22T20:13:05.262Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/jupyterhub/jupyterhub/security/advisories/GHSA-m68r-v472-jgq9",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/jupyterhub/jupyterhub/security/advisories/GHSA-m68r-v472-jgq9"
        },
        {
          "name": "https://github.com/jupyterhub/jupyterhub/commit/9c5ec277d3cda5a59de2d8c8117efa77bd941127",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/jupyterhub/jupyterhub/commit/9c5ec277d3cda5a59de2d8c8117efa77bd941127"
        }
      ],
      "source": {
        "advisory": "GHSA-m68r-v472-jgq9",
        "discovery": "UNKNOWN"
      },
      "title": "JupyterHub: Cross-origin form POSTs bypass XSRF"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-40864",
    "datePublished": "2026-05-22T20:13:05.262Z",
    "dateReserved": "2026-04-15T15:57:41.717Z",
    "dateUpdated": "2026-05-26T13:13:51.723Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-M68R-V472-JGQ9

Summary

Patches

Mitigations

CVE-2026-40864 (GCVE-0-2026-40864)

Tags

Sightings

Nomenclature