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CVE-2026-40110

CVE-2026-40110 · jupyter-server CORS origin validation bypass via unanchored regex in allow_origin_pat

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 7.6 · High · EPSS 0.5% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • jupyter_server

    Versions
    • <= 2.17.0: Affected

    No fix published

  • jupyter-server Debian:12

    Versions
    • 1.23.3-1
    • 1.23.3-2
    • 2.14.0-1
    • 2.14.2-1
    • 2.14.2-2
    • 2.14.2-3
    • 2.14.2-4
    • 2.14.2-5
    • 2.15.0-1
    • 2.17.0-1
    • 2.20.0-1
    • 2.20.0-2
    • 2.20.0-3
    • 2.9.1-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • jupyter-server Debian:13

    Versions
    • 2.15.0-1
    • 2.17.0-1
    • 2.20.0-1
    • 2.20.0-2
    • 2.20.0-3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • jupyter-server Debian:14

    Versions
    • 2.15.0-1
    • 2.17.0-1
    Affected ranges
    • ECOSYSTEM: < 2.20.0-1

    Update to 2.20.0-1

  • jupyter-server PyPI

    Versions
    • 0.0.0
    • 0.0.1
    • 0.0.2
    • 0.0.3
    • 0.0.4
    • 0.0.5
    • 0.1.0
    • 0.1.1
    • 0.2.0
    • 0.2.1
    • 0.3.0
    • 1.0.0
    • 1.0.0rc0
    • 1.0.0rc1
    • 1.0.0rc10
    • 1.0.0rc11
    • 1.0.0rc12
    • 1.0.0rc13
    • 1.0.0rc14
    • 1.0.0rc15
    • 1.0.0rc16
    • 1.0.0rc2
    • 1.0.0rc3
    • 1.0.0rc4
    • 1.0.0rc5
    • 1.0.0rc6
    • 1.0.0rc7
    • 1.0.0rc8
    • 1.0.0rc9
    • 1.0.1
    • 1.0.10
    • 1.0.11
    • 1.0.2
    • 1.0.3
    • 1.0.4
    • 1.0.5
    • 1.0.6
    • 1.0.7
    • 1.0.8
    • 1.0.9
    • 1.1.0
    • 1.1.1
    • 1.1.2
    • 1.1.3
    • 1.1.4
    • 1.10.0
    • 1.10.1
    • 1.10.2
    • 1.11.0
    • 1.11.1
    • 1.11.2
    • 1.12.0
    • 1.12.1
    • 1.13.0
    • 1.13.1
    • 1.13.2
    • 1.13.3
    • 1.13.4
    • 1.13.5
    • 1.15.0
    • 1.15.1
    • 1.15.2
    • 1.15.3
    • 1.15.4
    • 1.15.5
    • 1.15.6
    • 1.16.0
    • 1.17.0
    • 1.17.1
    • 1.18.0
    • 1.18.1
    • 1.19.0
    • 1.19.1
    • 1.2.0
    • 1.2.1
    • 1.2.2
    • 1.2.3
    • 1.21.0
    • 1.23.0
    • 1.23.1
    • 1.23.2
    • 1.23.3
    • 1.23.4
    • 1.23.5
    • 1.23.6
    • 1.24.0
    • 1.3.0
    • 1.4.0
    • 1.4.1
    • 1.5.0
    • 1.5.1
    • 1.6.0
    • 1.6.1
    • 1.6.2
    • 1.6.3
    • 1.6.4
    • 1.7.0
    • 1.7.0a1
    • 1.7.0a2
    • 1.8.0
    • 1.9.0
    • 2.0.0
    • 2.0.0a0
    • 2.0.0a1
    • 2.0.0a2
    • 2.0.0b0
    • 2.0.0b1
    • 2.0.0rc0
    • 2.0.0rc1
    • 2.0.0rc2
    • 2.0.0rc3
    • 2.0.0rc4
    • 2.0.0rc5
    • 2.0.0rc6
    • 2.0.0rc7
    • 2.0.0rc8
    • 2.0.1
    • 2.0.2
    • 2.0.3
    • 2.0.4
    • 2.0.5
    • 2.0.6
    • 2.0.7
    • 2.1.0
    • 2.10.0
    • 2.10.1
    • 2.11.0
    • 2.11.1
    • 2.11.2
    • 2.12.0
    • 2.12.1
    • 2.12.2
    • 2.12.3
    • 2.12.4
    • 2.12.5
    • 2.13.0
    • 2.14.0
    • 2.14.1
    • 2.14.2
    • 2.15.0
    • 2.16.0
    • 2.17.0
    • 2.2.0
    • 2.2.1
    • 2.3.0
    • 2.4.0
    • 2.5.0
    • 2.6.0
    • 2.7.0
    • 2.7.1
    • 2.7.2
    • 2.7.3
    • 2.8.0
    • 2.9.0
    • 2.9.1
    Affected ranges
    • ECOSYSTEM: < 2.18.0

    Update to 2.18.0

  • jupyter-server Ubuntu:22.04:LTS

    Versions
    • 1.2.2-1
    • 1.13.1-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • jupyter-server Ubuntu:24.04:LTS

    Versions
    • 1.23.3-1
    • 1.23.3-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • jupyter-server Ubuntu:25.10

    Versions
    • 2.14.2-5
    • 2.15.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • jupyter-server Ubuntu:26.10

    Versions
    • 2.17.0-1
    • 2.20.0-3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • jupyter-server Ubuntu:26.04:LTS

    Versions
    • 2.15.0-1
    • 2.17.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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