How severe is CVE-2021-41247?

CVE-2021-41247 has a CVSS 3.x base score of 3.5, rated low severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-41247 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-41247?

CVE-2021-41247 affects Jupyter Jupyterhub. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-41247?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-41247 published?

CVE-2021-41247 was published on 2021-11-04 and last updated on 2026-06-17.

CVE-2021-41247

CVE-2021-41247 is a low-severity vulnerability in Jupyter Jupyterhub with a CVSS 3.x base score of 3.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-613.

Key facts

Severity: Low (CVSS 3.x base score 3.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-613
Affected product: Jupyter Jupyterhub
Published: 2021-11-04
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-41247?: 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.
How severe is CVE-2021-41247?: CVE-2021-41247 has a CVSS 3.x base score of 3.5, rated low severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-41247 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41247?: CVE-2021-41247 affects Jupyter Jupyterhub. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-41247?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-41247 published?: CVE-2021-41247 was published on 2021-11-04 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:jupyter:jupyterhub:*:*:*:*:*:*:*:*

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