CVE-2026-85580 [MEDIUM] – SiYuan versions before v3.8.2 contain a path guard bypass vulnerability in the MCP file-ac

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.