Public mode

No access to your tenant or devices. Every item links to its source. What this means

CVE-2026-66012

SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP

CVSS 4.0 10.0 CRITICALCVSS 3.1 10.0 CRITICALCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-66012

Published

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.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-66012

Published

siyuan

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "siyuan-note",
                    "product": "siyuan",
                    "defaultStatus": "unaffected",
                    "packageURL": "pkg:golang/github.com/siyuan-note/siyuan",
                    "versions": [
                        {
                            "version": "0",
                            "status": "affected",
                            "versionType": "semver",
                            "lessThan": "3.7.2"
                        },
                        {
                            "version": "3.7.2",
                            "status": "unaffected",
                            "versionType": "semver"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON