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.

Project Subscriptions

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-5mrq-x3x5-8v8f Jupyter Server's Authentication Cookies Remain Valid After Password Reset and Server Restart
Fixes

Solution

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Workaround

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History

Tue, 05 May 2026 21:45:00 +0000

Type Values Removed Values Added
Description 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.
Title jupyter-server authentication cookies remain valid after password reset due to static cookie secret
Weaknesses CWE-613
References
Metrics cvssV4_0

{'score': 7.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-05T21:31:42.897Z

Reserved: 2026-04-15T20:40:15.518Z

Link: CVE-2026-40934

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-05T22:16:00.820

Modified: 2026-05-05T22:16:00.820

Link: CVE-2026-40934

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses