🛡️ CVE-2026-44727 on Ubuntu — jupyter-server

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

Distribution advisory

This page covers CVE-2026-44727 as tracked by Ubuntu, for the package jupyter-server. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. A user must be tricked into taking some action. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality low, integrity low, availability none.

Affected software

UBUNTU-CVE-2026-44727 is recorded against 1 package.

  • jupyter-server

Timeline and source

Published on 22 June 2026 and last revised on 30 June 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
github.com (Report)
github.com (Report)

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-06-22
Updated 2026-08-11
Modified 2026-06-30
Fix URL N/A

Affected Packages

Software From version Fixed in
jupyter-server — —

Similar Threats

Exploit Protection

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UBUNTU-CVE-2026-44727 carries CVSS 9.5 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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