What is CVE-2023-40170?

CVE-2023-40170 is a medium-severity vulnerability in Jupyter Server, classified under Improper Access Control. CVSS score: 4.6/10. Published 2023-08-28.

How severe is CVE-2023-40170?

Medium severity. CVSS v3 base score is 4.6 out of 10.

XSS in Jupyter Server

CVE-2023-40170

jupyter-server is the backend for Jupyter web applications. Improper cross-site credential checks on `/files/` URLs could allow exposure of certain file contents, or accessing files when opening untrusted files via "Open image in new tab". This issue has been addressed in commit `87a49272728` which has been included in release `2.7.2`. Users are advised to upgrade. Users unable to upgrade may use the lower performance `--ContentsManager.files_handler_class=jupyter_server.files.handlers.FilesHandler`, which implements the correct checks.

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

CVSS v3 metric

CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.006 (48.9th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Jupyter Server
Jupyter-Server Jupyter Server — versions < 2.7.2

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2023-40170?: CVE-2023-40170 is a medium-severity vulnerability in Jupyter Server, classified under Improper Access Control. CVSS score: 4.6/10. Published 2023-08-28.
How severe is CVE-2023-40170?: Medium severity. CVSS v3 base score is 4.6 out of 10.