What is CVE-2026-33709?

CVE-2026-33709 is a medium-severity vulnerability in Jupyter Jupyterhub, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2026-04-03.

How severe is CVE-2026-33709?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Open Redirect in Jupyter Jupyterhub

CVE-2026-33709

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 Jup…

Vulnerability class: Open Redirect

EPSS: 0.002 (13.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Jupyter Jupyterhub
Jupyterhub — versions < 5.4.4

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
security-advisories@github.com (Product, x_refsource_MISC)

Frequently asked questions

What is CVE-2026-33709?: CVE-2026-33709 is a medium-severity vulnerability in Jupyter Jupyterhub, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2026-04-03.
How severe is CVE-2026-33709?: Medium severity. CVSS v3 base score is 6.1 out of 10.