CVEvulnerability

CVE-2026-44727

9.3 CRITICAL Published 2026-06-22 Modified 2026-10-25 Official page ↗
Status
Modified
Published
2026-06-22
Last modified
2026-10-25
Assigner
[email protected]
CVSS 4.0 ([email protected])
9.3 CRITICAL — 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
CVSS 3.1 ([email protected])
5.4 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CVSS 3.1 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)
9.0 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Weaknesses
CWE-1021, CWE-79

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.

Affected configurations

• jupyter jupyter server (< 2.20.0)

Related

Weakness · CWE (2)

  • CWE-1021 Improper Restriction of Rendered UI Layers or Frames weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation weakness

References