CVE-2026-44727

Jupyter Server (prior to 2.20) is affected by a stored XSS in the nbconvert HTML export path. The nbconvert HTTP handlers NbconvertFileHandler and NbconvertPostHandler render notebook HTML under the Jupyter origin without a sandbox directive in Content-Security-Policy, and NbconvertHTMLExporter’s...

CVE-2026-44727: Improper Neutralization of Input During Web Page Generation

Jupyter Server is the backend for Jupyter web applications. Prior to 2.20, the nbconvert HTTP handlers in jupyterserver render user-authored notebook HTML under the Jupyter origin without a sandbox directive in their Content-Security-Policy. Combined with nbconvert.HTMLExporter's default...