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

中 4.3CVE-2026-40864 · BIT-jupyterhub-2026-40864 · GHSA-m68r-v472-jgq9 · 22/05/2026 公開 · 23/07/2026 更新

要点

CVE-2026-40864 は jupyterhub, jupyterhub (jupyter) に影響する深刻度「中」 (CVSS 4.3) の脆弱性です。
今後30日間に悪用される確率（EPSS）：0.15%（全脆弱性の 3.8% より高い）。
対処：5.4.5 以降に更新してください。

パッケージ	影響を受けるバージョン	修正済みバージョン
jupyterhub PyPI	`≥ 4.1.0, < 5.4.5`	`5.4.5`
jupyterhub jupyter	`≥ 4.1.0, < 5.4.5`	`5.4.5`

概要

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.

NVD の説明

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.