---
id: CVE-2026-66012
title: >-
  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
summary: >-
  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, i…
severity: critical
cvss: 10
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H'
cwe:
  - CWE-862
vendor: siyuan-note
product: siyuan
affected:
  - siyuan < 3.7.2
published: '2026-07-25'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T18:17:02.667'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-66012'
references:
  - url: >-
      https://github.com/siyuan-note/siyuan/commit/c72ca4cd09019e5f64afdee8f8c6ec5ef34858db
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cvhv-7xhj-xjp8
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/siyuan-before-unauthenticated-administrator-takeover-via-mcp
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cvhv-7xhj-xjp8
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-07-27T14:06:39.063655Z'
epss: 0.00764
epssPercentile: 0.53441
exploits:
  github: 1
  githubRepos:
    - >-
      https://github.com/Hunt-Benito/siyuan-mcp-admin-takeover-cve-2026-66012-missing-authorization
  checkedAt: '2026-09-25T08:21:08.011Z'
ingestedAt: '2026-07-26T11:12:02.968Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.