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CVE-2026-6657

CVE-2026-6657 · CORS Origin Validation Bypass in jupyter-server

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

A vulnerability in jupyter-server versions 1.12.0 through 2.17.0 allows an attacker to bypass CORS origin validation when the `allow_origin_pat` configuration is used. The issue arises from the use of `re.match()` for validating the `Origin` header, which only anchors at the start of the string. This allows attacker-controlled domains such as `trusted.example.com.evil.com` to pass validation against patterns intended to match `trusted.example.com`. The vulnerability affects multiple locations in the codebase, including CORS headers, WebSocket connections, referer validation, and login redirects, potentially enabling phishing attacks, arbitrary code execution, and unauthorized access to sensitive API responses.

CVSS 6.1 · Medium · EPSS 0.3%

Published
Updated

Stack: system · python

Affected products and versions

  • jupyter/jupyter

    Versions
    • ≥ unspecified, ≤ latest: Affected (custom)

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

    No fix published

  • jupyter-server PyPI

    Versions
    • 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
    • 1.21.0
    • 1.23.0
    • 1.23.1
    • 1.23.2
    • 1.23.3
    • 1.23.4
    • 1.23.5
    • 1.23.6
    • 1.24.0
    • 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: ≥ 1.12.0, ≤ 2.17.0

    No fix published

  • 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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