CVE-2026-66012 - SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP

CVE-2026-66012 - SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP

https://cvefeed.io/rssfeed/latest.atom / Sat, 07/25/2026 - 19:07
CVE ID :CVE-2026-66012
Published : July 25, 2026, 11:17 a.m. | 5 hours, 34 minutes ago
Description :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.
Severity: 10.0 | CRITICAL
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