CVE-2026-33709: JupyterHub is software that allows one to create a multi-user server for Jupyter notebooks

Q: How do I fix CVE-2026-33709?

jupyterhub: upgrade to 5.4.4. Exact commands for each OS are on this page.

Q: Is CVE-2026-33709 being exploited?

CVE-2026-33709 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-33709 affect?

CVE-2026-33709 affects jupyterhub. Severity is medium (CVSS 6.1). JupyterHub is software that allows one to create a multi-user server for Jupyter notebooks. Prior to version 5.4.4, an open redirect vulnerability in JupyterHub allows attackers to construct links which, when clicked, take users to the Jupy

Q: How urgent is CVE-2026-33709?

Priority 24/100. No elevated risk signals yet.

Routine

MEDIUM 6.1UPGRADE

CVE-2026-33709 is a medium-severity flaw (CVSS 6.1) affecting jupyterhub. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

JupyterHub is software that allows one to create a multi-user server for Jupyter notebooks. Prior to version 5.4.4, an open redirect vulnerability in JupyterHub allows attackers to construct links which, when clicked, take users to the JupyterHub login page, after which they are sent to an arbitrary attacker-controlled site outside JupyterHub instead of a JupyterHub page, bypassing JupyterHub's check to prevent this. This issue has been patched i

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 89%)
CISA exploited list	No
Weakness	CWE-601
Published	2026-04-03
Last modified	2026-07-24

Publisher (CNA): GitHub, Inc. · Vendor: jupyter

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-03 22:16 UTCPublished CVE record published
2026-07-24 22:10 UTCUpdated Record last modified

jupyter jupyterhub UPGRADE

Affected: < 5.4.4

Fixed in: 5.4.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy jupyterhub || rpm -q jupyterhub || jupyterhub --version

2. UPGRADE to 5.4.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade jupyterhub

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade jupyterhub

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-33709?

jupyterhub: upgrade to 5.4.4. Exact commands for each OS are on this page.

Is CVE-2026-33709 being exploited?

CVE-2026-33709 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-33709 affect?

CVE-2026-33709 affects jupyterhub. Severity is medium (CVSS 6.1). JupyterHub is software that allows one to create a multi-user server for Jupyter notebooks. Prior to version 5.4.4, an open redirect vulnerability in JupyterHub allows attackers to construct links which, when clicked, take users to the Jupy

How urgent is CVE-2026-33709?

Priority 24/100. No elevated risk signals yet.

Software pages

Jupyter vulnerabilities

Related CVEs

CVE-2026-40864 MEDIUM 5.4 UPGRADE JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks

References

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