CVE-2026-66394

CRITICAL CVSS 4.0: 9.3 EPSS 0.27%
Updated Jul 28, 2026
Siyuan-Note
Parameter Value
CVSS 9.3 (CRITICAL)
Type CWE-79 (Cross-Site Scripting (XSS))
Vendor Siyuan-Note
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
Low
Basic privileges needed
User Interaction
Passive
Minimal interaction

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
None
No disruption

CVSS Vector v4.0

Vulnerable Products

siyuan-note:siyuan