by Kastro CVE-2026-44727
jupyter-server jupyter_server — Jupyter Server: Stored XSS in `NbconvertFileHandler` / `NbconvertPostHandler` via missing `sandbox` CSP
Description · from the CVE record
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.
Affected
ProductAffectedFixed inSource
jupyter_server< 2.20–CNA
Red Hat Migration Toolkit for Applications 8.2see advisory1784109883redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787076778redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787077779redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787076481redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787074331redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787073913redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787074078redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787073929redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787073605redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787073546redhat-SADP
Red Hat OpenShift AI 3.4see advisory1787073717redhat-SADP
Scores by source
GitHub_M (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
redhat-SADP (CNA)9.0CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total