Missing authorization on MCP endpoint in SiYuan (CVE-2026-66012)

The POST /mcp endpoint in the SiYuan kernel exposes 31 MCP tools - including file list, read, write, delete, rename, and copy operations across the entire workspace - gated only by a general authentication check (model.CheckAuth) with no admin-role or read-only enforcement. When the Publish server is enabled in anonymous mode (Conf.Publish.Enable=true and Conf.Publish.Auth.Enable=false), the Publish reverse proxy unconditionally attaches an anonymous RoleReader JWT to every proxied request, granting unauthenticated remote attackers access to all MCP tools. An attacker can read conf/conf.json to extract accessAuthCode, api.token, and cookieKey in plaintext, write arbitrary files in the workspace, or plant a plugin into data/plugins/ that executes with nodeIntegration:true and no contextIsolation on the next desktop launch, resulting in administrator takeover. Affected versions: - 3.7.1 We recommend updating to: v3.7.2. CVSS 10.0 · our assessment: act_now Reference: https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cvhv-7xhj-xjp8 Details: https://vuln.today/cve/CVE-2026-66012