CVE-2026-87814

HIGH CVSS 4.0: 8.4 EPSS 0.37%
Updated Sep 18, 2026
B3Log
Parameter Value
CVSS 8.4 (HIGH)
Affected Versions before 3.8.2
Fixed In 3.8.2
Type CWE-79 (Cross-Site Scripting (XSS))
Vendor B3Log
Public PoC No

SiYuan before v3.8.2 contains a stored cross-site scripting vulnerability in the search asset preview feature that fails to escape indexed asset content before inserting it into the DOM using innerHTML. Attackers who can place crafted text assets in a workspace can execute JavaScript in the SiYuan origin when victims preview the assets, enabling authenticated API requests and workspace manipulation.

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
Active
User action required

Impact Assessment

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

CVSS Vector v4.0

Vulnerable Products 1

Configuration From (including) Up to (excluding)
B3log Siyuan
cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*
— 3.8.2