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CVE-2026-86049

CVE-2026-86049 · Jupyter Server: 5xx request logging leaks token-bearing Referer header values

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

Jupyter Server is the backend for Jupyter web applications. Prior to version 2.21.0, the 5xx request logging path in jupyter_server/log.py copies the Referer header into a JSON header block without applying the token scrubbing used for the request URI. A request that returns HTTP 500 while the Referer contains a token-bearing URL can therefore write that token to server logs in plaintext. An attacker who can read those logs can recover the token and use the affected user's Jupyter Server permissions. This issue is fixed in version 2.21.0.

CVSS 7.1 · High · EPSS 0.4% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • jupyter_server

    Versions
    • < 2.21.0: 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
    • 2.20.0-1
    • 2.20.0-2
    • 2.20.0-3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • 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
    • 2.18.0
    • 2.18.1
    • 2.18.2
    • 2.19.0
    • 2.2.0
    • 2.2.1
    • 2.20.0
    • 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: < 2.21.0

    Update to 2.21.0

  • 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: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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