Siyuan · Siyuan · CVE-2026-66012
**Name of the Vulnerable Software and Affected Versions**
SiYuan versions prior to 3.7.2
**Description**
A missing authorization issue exists in the 'POST /mcp' kernel endpoint, which is only protected by a general authentication check `model.CheckAuth()` without enforcing admin roles or read-only restrictions. This flaw exposes 31 MCP tools, including a file tool capable of listing, reading, writing, deleting, renaming, and copying files across the entire workspace. If the Publish server is configured in anonymous mode (`Conf.Publish.Enable=true` and `Conf.Publish.Auth.Enable=false`), the reverse proxy attaches an anonymous RoleReader JWT to requests, enabling unauthenticated remote attackers to access the endpoint. An attacker can extract `accessAuthCode`, `api.token`, and `cookieKey` in plaintext from `conf/conf.json`, write arbitrary files, and install a malicious plugin in `data/plugins/` that executes with `nodeIntegration:true` and no `contextIsolation` upon the next desktop launch, resulting in full administrator takeover.
**Recommendations**
Update to version 3.7.2 or later.
As a temporary mitigation, disable the Publish server anonymous mode by setting `Conf.Publish.Enable=false` or `Conf.Publish.Auth.Enable=true`.