CVE-2026-44727
Our Analysis: General Purpose
Our model has classified this vulnerability as relevant to General Purpose Systems, helping your team prioritize efforts effectively.
Published Date
June 22, 2026
Last Modified
June 22, 2026
CVSS Vector
Not Available
Description
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.