Jupyter Server has a CORS Origin Validation Bypass via `re.match()` in `allow_origin_pat`

高 7.3CVE-2026-40110 · GHSA-24qx-w28j-9m6p · PYSEC-2026-2187 · 05/05/2026 公開 · 24/07/2026 更新

要点

CVE-2026-40110 は jupyter-server, jupyter server (jupyter) に影響する深刻度「高」 (CVSS 7.3) の脆弱性です。
今後30日間に悪用される確率（EPSS）：0.31%（全脆弱性の 24.2% より高い）。
対処：2.18.0 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
jupyter-server PyPI	`< 2.18.0`	`2.18.0`
jupyter server jupyter	`< 2.18.0`	`2.18.0`

概要

Jupyter Server uses re.match() to validate the Origin header against the allow_origin_pat configuration.

Since re.match() only anchors at the start of the string, an attacker who controls a domain like http://trusted.example.com.evil.com/ passes validation against a pattern intended to match only trusted.example.com.

Impact

<=2.17.0

Patches

057869a327c46730afede3eab0ca2d2e3e74acea, 49b34392feaa97735b3b777e3baf8f22f2a14ed8

Workarounds

Wrap your allow_origin_pat value with ^ and $

References

https://github.com/jupyter-server/jupyter_server/pull/603 https://docs.python.org/3/library/re.html#re.fullmatch https://docs.python.org/3/library/re.html#re.match

NVD の説明

Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, the Origin header validation uses Python's re.match() to check incoming origins against the allow_origin_pat configuration value. Because re.match() only anchors at the start of the string and does not require a full match, a pattern intended to match only a trusted domain (e.g., trusted.example.com) will also match any origin that begins with that domain followed by additional characters (e.g., trusted.example.com.evil.com). An attacker who controls such a domain can bypass the CORS origin restriction and make cross-origin requests to the Jupyter Server API from an untrusted site. This issue has been fixed in version 2.18.0.