CVE-2026-66012
CriticalCVSS 10.0Exploitation Probability (EPSS)
Low risk36th percentile - higher than 36% of all known CVEs
Summary
SiYuan before v3.7.2 contains a missing authorization vulnerability in the POST /mcp kernel endpoint, gated only by a general auth check with no admin-role or read-only enforcement, exposing 31 MCP tools including file operations across the entire workspace.
Risk Assessment
An attacker can read conf/conf.json to extract accessAuthCode, api.token, and cookieKey, write arbitrary files in the workspace, and plant a plugin that executes with full privileges, leading to administrator takeover.
Recommendation
Update SiYuan to version v3.7.2 or later. Disable the Publish server in anonymous mode if not required.
Original NVD description (English source)
SiYuan before v3.7.2 contains a missing authorization vulnerability in the POST /mcp kernel endpoint, which is gated only by a general auth check (model.CheckAuth) with no admin-role or read-only enforcement. This exposes 31 MCP tools, including a file tool with list/read/write/delete/rename/copy actions across the entire workspace. When the Publish server is enabled in anonymous mode (Conf.Publish.Enable=true and Conf.Publish.Auth.Enable=false), the Publish reverse proxy attaches an anonymous RoleReader JWT to proxied requests, allowing a remote unauthenticated attacker to reach /mcp. The attacker can read conf/conf.json to extract accessAuthCode, api.token, and cookieKey in plaintext, write arbitrary files in the workspace, and plant a plugin into data/plugins/ that executes with nodeIntegration:true and no contextIsolation on the next desktop launch, leading to administrator takeover.