> CVE-2026-66394 [CRITICAL]

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PUBLISHED
2026-07-27 16:18
MODIFIED
2026-07-27 16:18
CVSS_SCORE V3
9.3
EPSS (Prob. Exploit)
0.34%
Top 74.1%
DATA SOURCES:
NVD 🔗 2026-07-27 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-10-25 OSV 🔗 2026-08-03

> DESCRIPTION

SiYuan before v3.7.3 contains stored and reflected cross-site scripting vulnerabilities in SVG sanitization that allows authenticated attackers to execute scripts by bypassing the HTML parser-based cleaner. Attackers can hide script tags within desc, style, or noscript elements which the HTML parser treats as raw text but browsers interpret as executable SVG content when served as image/svg+xml, enabling script execution in the application origin.

> 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:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/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:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/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
Unknown (P)
Interaction inconnue
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
None (N)
Aucune interruption de service

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
None
Aucune interruption de service

> WEAKNESSES

CWE-79

> 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.

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

SiYuan before v3.7.3 Stored and Reflected XSS via SVG Sanitizer Bypass

AFFECTED PACKAGES:
Unknown / Unknown
689 versions affected
ALIASES:
GHSA-99rq-75j6-5j9f

> HISTORIQUE DES MODIFICATIONS

Première apparition
27/07/2026 16:18
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 01/08/2026 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: 4 days ago

> REFERENCES

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-99rq-75j6-5j9f
https://www.vulncheck.com/advisories/siyuan-before-stored-and-reflected-xss-via-...
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