CVE-2026-66012

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.

CVSS v3 10.0 CRITICAL

10.0^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 6.0

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope CHANGED

References

Link	Resource
https://github.com/siyuan-note/siyuan/commit/c72ca4cd09019e5f64afdee8f8c6ec5ef34858db
https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cvhv-7xhj-xjp8
https://www.vulncheck.com/advisories/siyuan-before-unauthenticated-administrator-takeover-via-mcp
https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cvhv-7xhj-xjp8

Configurations

No configuration.

History

No history.

Information

Published : 2026-07-25 11:17

Updated : 2026-09-17 18:17

NVD link : CVE-2026-66012

Mitre link : CVE-2026-66012

CVE.ORG link : CVE-2026-66012

JSON object : View

Products Affected

No product.

CWE

CWE-862

Missing Authorization

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