CVE-2026-74800

CRITICAL CVSS 4.0: 9.4 EPSS 0.29%
Updated Aug 26, 2026
SiYuan
Parameter Value
CVSS 9.4 (CRITICAL)
Type CWE-79 (Cross-Site Scripting (XSS))
Vendor SiYuan
Public PoC No

SiYuan before v3.7.4 fails to set Content-Disposition and X-Content-Type-Options headers when serving arbitrary file assets, allowing stored cross-site scripting attacks. Authenticated attackers can upload HTML files as assets and execute scripts with full kernel API access when the workspace owner opens the asset link.

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
High
Complete denial of service

CVSS Vector v4.0