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Information Exposure Through Log Files Affecting jupyter-server package, versions *

Severity

 Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.24% (16th percentile)

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  • Snyk IDSNYK-ECHOLATEST-JUPYTERSERVER-19946178
  • published19 Sept 2026
  • disclosed17 Sept 2026
Report a new vulnerability Found a mistake?

Introduced: 17 Sep 2026

NewCVE-2026-86049  (opens in a new tab)
CWE-532  (opens in a new tab)

How to fix?

There is no fixed version for Echo:latest jupyter-server.

NVD Description

Note: Versions mentioned in the description apply only to the upstream jupyter-server package and not the jupyter-server package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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.