CVE-2026-100636

HIGH CVSS 4.0: 8.3 EPSS 0.54%
Updated Sep 28, 2026
B3Log
Parameter Value
CVSS 8.3 (HIGH)
Affected Versions before 3.8.4
Fixed In 3.8.4
Type CWE-22 (Path Traversal)
Vendor B3Log
Public PoC No

SiYuan versions before v3.8.4 contain a path traversal vulnerability in the exportBrowserHTML endpoint that allows authenticated administrators to write arbitrary HTML content to index.html outside the workspace directory. Attackers can supply a folder parameter with directory traversal sequences to escape the export directory and overwrite index.html in any pre-existing kernel-writable location, enabling stored XSS or workspace defacement.

Attack Parameters

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

Impact Assessment

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

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products 1

Configuration From (including) Up to (excluding)
B3log Siyuan
cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*
— 3.8.4