What is CVE-2023-39968?

CVE-2023-39968 is a medium-severity vulnerability in Jupyter Server, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 4.3/10. Published 2023-08-28.

How severe is CVE-2023-39968?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Open Redirect in Jupyter Server

CVE-2023-39968

jupyter-server is the backend for Jupyter web applications. Open Redirect Vulnerability. Maliciously crafted login links to known Jupyter Servers can cause successful login or an already logged-in session to be redirected to arbitrary sites, which should be restricted to Jupyter Server-served URLs. This issue has been addressed in commit `29036259` which is included in release 2.7.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Vulnerability class: Open Redirect

Published 2023-08-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.007 (51.5th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Jupyter Server
Jupyter-Server Jupyter Server — versions < 2.7.2

Weakness classification (CWE)

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

References

Frequently asked questions

What is CVE-2023-39968?: CVE-2023-39968 is a medium-severity vulnerability in Jupyter Server, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 4.3/10. Published 2023-08-28.
How severe is CVE-2023-39968?: Medium severity. CVSS v3 base score is 4.3 out of 10.