CVE-2026-44727 Common Vulnerabilities and Exposures

Upstream information

CVE-2026-44727 at MITRE

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.

Other Security Trackers

EUVD-2026-38347

SUSE information

Overall state of this security issue: Resolved

This issue is currently rated as having critical severity.

CVSS v3 Scores
CVSS detail	CNA (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)	National Vulnerability Database
Base Score	9	5.4
Vector	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Attack Vector	Network	Network
Attack Complexity	Low	Low
Privileges Required	Low	Low
User Interaction	Required	Required
Scope	Changed	Changed
Confidentiality Impact	High	Low
Integrity Impact	High	Low
Availability Impact	High	None
CVSSv3 Version	3.1	3.1

CVSS v4 Scores
CVSS detail	CNA (GitHub)
Base Score	9.3
Vector	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector	Network
Attack Complexity	Low
Attack Requirements	None
Privileges Required	Low
User Interaction	Active
Vulnerable System Confidentiality Impact	High
Vulnerable System Integrity Impact	High
Vulnerable System Availability Impact	High
Subsequent System Confidentiality Impact	High
Subsequent System Integrity Impact	High
Subsequent System Availability Impact	High
CVSSv4 Version	4.0

SUSE Bugzilla entry: 1269630 [IN_PROGRESS]

No SUSE Security Announcements cross referenced.

List of released packages

Product(s)	Fixed package version(s)	References
openSUSE Tumbleweed	`python311-jupyter-server >= 2.20.0-1.1` `python311-jupyter-server-test >= 2.20.0-1.1` `python313-jupyter-server >= 2.20.0-1.1` `python313-jupyter-server-test >= 2.20.0-1.1` `python314-jupyter-server >= 2.20.0-1.1` `python314-jupyter-server-test >= 2.20.0-1.1`	Patchnames: openSUSE-Tumbleweed-2026-11159

SUSE Timeline for this CVE

CVE page created: Fri Jun 19 00:00:17 2026
CVE page last modified: Wed Jul 1 20:40:05 2026