CVE-2026-85580: Siyuan-Note Siyuan

Medium severity, CVSS 6.5. EPSS: 0.6% chance of exploitation in the next 30 days.

SiYuan versions before v3.8.2 contain a path guard bypass vulnerability in the MCP file-access handler that uses case-sensitive matching on Linux filesystems. Attackers can read the protected publishAccess.json file by requesting case-variant paths like PublishAccess.json to disclose sensitive publish-access configuration and metadata.

Affected products

• Siyuan-Note Siyuan: before 3.8.2 (fixed in 3.8.2)

Published 2026-09-04. Last modified 2026-09-08.