Insufficient Session Expiration Affecting jupyter-server package, versions <2.20.0-1


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.31% (23rd percentile)

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  • Snyk IDSNYK-DEBIAN14-JUPYTERSERVER-16427714
  • published6 May 2026
  • disclosed5 May 2026

Introduced: 5 May 2026

CVE-2026-40934  (opens in a new tab)
CWE-613  (opens in a new tab)

How to fix?

Upgrade Debian:14 jupyter-server to version 2.20.0-1 or higher.

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 Debian. See How to fix? for Debian:14 relevant fixed versions and status.

Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, the secret used to sign authentication cookies is persisted to a static file at ~/.local/share/jupyter/runtime/jupyter_cookie_secret and is never rotated when a user changes their password. After a password reset and server restart, any previously issued authentication cookie remains cryptographically valid because the signing key has not changed. An attacker who has captured a session cookie through any means retains full authenticated access to the server regardless of subsequent password changes. This affects deployments using password-based authentication, particularly shared or public-facing servers where credential rotation is expected to revoke existing sessions. This issue has been fixed in version 2.18.0.

CVSS Base Scores

version 3.1