CVE-2026-44727

EUVD-2026-38347

22.06.2026, 21:16

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.

Cross-site Scripting

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	5.4 MEDIUM	NETWORK	LOW	LOW	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Base Score

CVSS 3.x

EPSS Score

Percentile: 37.52%

Affected Products (NVD)

Vendor	Product	Version
jupyter	jupyter_server	𝑥 < 2.20.0

𝑥

= Vulnerable software versions

Early Detection

Affected products identified ahead of NVD analysis through intelligence sources.

Vendor	Product	Version	Source
Red Hat	Red Hat Migration Toolkit for Applications 8.2	1784109883 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787076778 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787077779 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787076481 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787074331 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787073913 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787074078 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787073929 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787073605 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787073546 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787073717 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787073713 ≤ 𝑥 < *	ADP
Red Hat	Red Hat OpenShift AI 3.4	1787073593 ≤ 𝑥 < *	ADP