CVE-2026-44727

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.
Configurations

Configuration 1 (hide)

cpe:2.3:a:jupyter:jupyter_server:*:*:*:*:*:*:*:*

History

22 Jul 2026, 12:18

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:43038 -

30 Jun 2026, 03:20

Type Values Removed Values Added
References
  • () https://access.redhat.com/security/cve/CVE-2026-44727 -
  • () https://bugzilla.redhat.com/show_bug.cgi?id=2491516 -
  • () https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44727.json -
References () https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-fcw5-x6j4-ccmp - Patch, Vendor Advisory, Mitigation () https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-fcw5-x6j4-ccmp - Mitigation, Patch, Vendor Advisory

26 Jun 2026, 18:57

Type Values Removed Values Added
References () https://github.com/jupyter-server/jupyter_server/commit/6cbee8d65e71abac851c4492fea987ad080580bd - () https://github.com/jupyter-server/jupyter_server/commit/6cbee8d65e71abac851c4492fea987ad080580bd - Patch
References () https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-fcw5-x6j4-ccmp - () https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-fcw5-x6j4-ccmp - Patch, Vendor Advisory, Mitigation
CPE cpe:2.3:a:jupyter:jupyter_server:*:*:*:*:*:*:*:*
First Time Jupyter jupyter Server
Jupyter
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 5.4

22 Jun 2026, 21:16

Type Values Removed Values Added
New CVE

Information

Published : 2026-06-22 21:16

Updated : 2026-07-22 12:18


NVD link : CVE-2026-44727

Mitre link : CVE-2026-44727

CVE.ORG link : CVE-2026-44727


JSON object : View

Products Affected

jupyter

  • jupyter_server
CWE
CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CWE-1021

Improper Restriction of Rendered UI Layers or Frames