Cross-site Scripting (XSS) Affecting jupyter-server package, versions *


Severity

Recommended
low

Based on Debian security rating.

Threat Intelligence

EPSS
0.44% (37th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-DEBIAN11-JUPYTERSERVER-17445444
  • published25 Jun 2026
  • disclosed22 Jun 2026

Introduced: 22 Jun 2026

CVE-2026-44727  (opens in a new tab)
CWE-79  (opens in a new tab)
CWE-1021  (opens in a new tab)

How to fix?

There is no fixed version for Debian:11 jupyter-server.

NVD Description

Note: Versions mentioned in the description apply only to the upstream jupyter-server package and not the jupyter-server package as distributed by Debian. See How to fix? for Debian:11 relevant fixed versions and status.

Jupyter Server is the backend for Jupyter web applications. Prior to 2.20, the nbconvert HTTP handlers in jupyter_server render user-authored notebook HTML under the Jupyter origin without a sandbox directive in their Content-Security-Policy. Combined with nbconvert.HTMLExporter's default non-sanitizing behavior, a notebook carrying an HTML payload in a display_data output triggers stored XSS with cookie access, full /api/* authority, and kernel RCE. This vulnerability is fixed in 2.20.

CVSS Base Scores

version 3.1