PT-2026-64762 · Siyuan Note · Siyuan

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CVE-2026-66012

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Published

2026-07-25

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Updated

2026-07-25

CVSS v3.1

10

Critical

VectorAV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
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.

Fix

Missing Authorization

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Weakness Enumeration

Related Identifiers

CVE-2026-66012

Affected Products

Siyuan