{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-66012","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","state":"PUBLISHED","assignerShortName":"VulnCheck","dateReserved":"2026-07-23T19:22:30.643Z","datePublished":"2026-07-25T10:45:56.085Z","dateUpdated":"2026-07-25T10:45:56.085Z"},"containers":{"cna":{"providerMetadata":{"orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck","dateUpdated":"2026-07-25T10:45:56.085Z"},"datePublic":"2026-07-13T00:00:00.000Z","title":"SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP","descriptions":[{"lang":"en","value":"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."}],"problemTypes":[{"descriptions":[{"lang":"en","description":"Missing Authorization","cweId":"CWE-862","type":"CWE"}]}],"affected":[{"vendor":"siyuan-note","product":"siyuan","defaultStatus":"unaffected","packageURL":"pkg:npm/github.com/siyuan-note/siyuan","versions":[{"version":"0","status":"affected","versionType":"semver","lessThan":"3.7.2"},{"version":"3.7.2","status":"unaffected","versionType":"semver"}]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"HIGH","subIntegrityImpact":"HIGH","subAvailabilityImpact":"HIGH","baseScore":10,"baseSeverity":"CRITICAL"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseScore":10,"baseSeverity":"CRITICAL"}}],"references":[{"url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cvhv-7xhj-xjp8","name":"GitHub Security Advisory (GHSA-cvhv-7xhj-xjp8)","tags":["vendor-advisory"]},{"url":"https://github.com/siyuan-note/siyuan/commit/c72ca4cd09019e5f64afdee8f8c6ec5ef34858db","name":"https://github.com/siyuan-note/siyuan/commit/c72ca4cd09019e5f64afdee8f8c6ec5ef34858db","tags":["patch"]},{"name":"VulnCheck Advisory: SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/siyuan-before-unauthenticated-administrator-takeover-via-mcp"}],"credits":[{"lang":"en","value":"hypnguyen1209","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}}}}