CVE-2021-41247

incomplete logout in JupyterHub

HIGH
7.5
CVSS Score
Published: November 4, 2021 at 05:15 PM UTC
Updated: June 17, 2026 at 04:08 AM UTC
2 products affected across 2 vendorsJupyterhubJupyterhub

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Severity
HIGH7.5
Exploit prediction
EPSS 0.8%

Description

JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

1.0.0 ≤ v < 1.5.0
Affected range stops below 1.5.0, so it looks safe — our inference, not a vendor statement
v < 1.2.0v < 1.5.0
Affected range stops below 1.2.0, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.5.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-613

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