> CVE-2026-44727 [CRITICAL]

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PUBLISHED
2026-06-22 21:16
MODIFIED
2026-06-22 21:16
CVSS_SCORE V3
9.3
EPSS (Prob. Exploit)
0.44%
Top 62.9%
DATA SOURCES:
NVD 🔗 2026-06-22 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-10-25 GITHUB 🔗 2026-11-05

> 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_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_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

> MÉTRIQUES CVSS DÉTAILLÉES

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
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
Low (L)
Authentifié avec compte utilisateur basique
UI (Interaction Utilisateur)
User Interaction
Required (R)
Nécessite une action utilisateur (clic lien, ouverture fichier, etc.)
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-79 CWE-1021

> CWE DETAILED DESCRIPTIONS

CWE-79: Improper Neutralization of Input During Web Page Generation - The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. | CWE-1021: Improper Restriction of Rendered UI Layers or Frames - The web application does not restrict or incorrectly restricts frame objects or UI layers that belong to another application or domain.

> RED HAT SECURITY ADVISORIES

Red Hat Security Advisory: Migration Toolkit for Applications
A new version of Migration Toolkit for Applications (MTA) is now available.
Red Hat Security Advisory: RHOAI 3.4.4 - Red Hat OpenShift AI
Updated images are now available for Red Hat OpenShift AI.
Red Hat Security Advisory: RHOAI 3.3.7 - Red Hat OpenShift AI
Updated images are now available for Red Hat OpenShift AI.

> GITHUB SECURITY ADVISORY

GHSA-fcw5-x6j4-ccmp CRITICAL

Jupyter Server: Stored XSS in `NbconvertFileHandler` / `NbconvertPostHandler` via missing `sandbox` CSP

AFFECTED PACKAGES:
PIP / jupyter-server
<= 2.19.0
Fixed in: 2.20.0

> HISTORIQUE DES MODIFICATIONS

Première apparition
22/06/2026 21:16
Source: NVD
📊 ENRICHISSEMENT 01/11/2026 06:59
CWE
Champ modifié: Description CWE
Ancienne valeur:
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') - The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in...
Nouvelle valeur:
CWE-79: Improper Neutralization of Input During Web Page Generation - The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a...
📊 ENRICHISSEMENT 01/07/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') - The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in...
Total des modifications: 2 Dernière mise à jour: 5 days ago

> REFERENCES

https://github.com/jupyter-server/jupyter_server/commit/6cbee8d65e71abac851c4492...
https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-fcw5-x...
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