Insertion of Sensitive Information into Log File Affecting jupyter-server package, versions [,2.21.0)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published22 Sept 2026
- disclosed17 Sept 2026
- creditDavid Carliez
Introduced: 17 Sep 2026
NewCVE-2026-86049 (opens in a new tab)How to fix?
Upgrade jupyter-server to version 2.21.0 or higher.
Overview
Affected versions of this package are vulnerable to Insertion of Sensitive Information into Log File via the log_request function in jupyter_server/log.py, which logs the full Referer header value without sanitization. When a request causes a 500 error, the Referer header - which may contain an authentication token embedded as a query parameter - is written verbatim to server logs, exposing the token to anyone with log access. The fix scrubs sensitive query parameters from the Referer URI before logging.