CVE-2026-86049

Jupyter Server (the backend for Jupyter web applications) prior to version 2.21.0 contains a token-leak flaw in the 5xx request logging path within jupyter_server/log.py. The Referer header is copied into a JSON header block without applying the same token scrubbing used for the request URI. When...

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

Jupyter Server is the backend for Jupyter web applications. Prior to version 2.21.0, the 5xx request logging path in jupyterserver/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...