CVE-2021-41247

mediumpriority · track · 30EPSS 0.008 · 57 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.80% (57th) EPSS

CVSS 5 · medium

Is it mine?

5 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · osv · nvd

EPSS · scored 2026-10-28

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.

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–high · 3.5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.13.5lowCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:Nsecondary · ENISA EU

v3.13.5lowCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:Nsecondary · security-advisories@github.comexploitability 2.1 · impact 1.4

v3.13.5lowCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:Nsecondary · OSV

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-613USprimaryCWE-613US

affected products (5)

Products and version ranges known to be affected.

jupyterhub jupyterhub≤ < 1.2.0 - jupyterhub (helm)enisa_euvdEU
jupyterhub jupyterhub1.0.0, → 1.5.0 - jupyterhub (pip)enisa_euvdEU
jupyter jupyterhub1.0.0 → 1.5.0nvdUScpe:2.3:a:jupyter:jupyterhub:*:*:*:*:*:*:*:*
Bitnami jupyterhub1.0.0 → 1.5.0osvUSpkg:bitnami/jupyterhub
PyPI jupyterhub1.0.0 → 1.5.0osvUSpkg:pypi/jupyterhub

advisories (3)

Vendor and ecosystem advisories describing this.

GHSA-cw7p-q79f-m2v7incomplete JupyterHub logout with simultaneous JupyterLab sessions2021-11-08ghsa · osvUS
### Impact Users of JupyterLab with JupyterHub 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. ### Patches 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. ### Workarounds The only workaround is to make sure that only one JupyterLab tab is open when you log out.
BIT-jupyterhub-2021-41247incomplete logout in JupyterHub2024-03-06vendor · osvUS
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.
PYSEC-2021-3862021-11-04vendor · osvUS
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.

also known as (7)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv nvd NVD CVE.org MITRE

published 2021-11-04modified 2026-06-17

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+728 more

references (7)

External citations — patches, advisories, analysis.

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