{"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":0.00553,"epssPercentile":0.44822,"exploits":{"github":1,"githubRepos":["https://github.com/Hunt-Benito/siyuan-mcp-admin-takeover-cve-2026-66012-missing-authorization"],"checkedAt":"2026-09-21T15:30:10.268Z"},"ingestedAt":"2026-07-26T11:12:02.968Z","slug":"CVE-2026-66012","body":"## Overview\n\nSiYuan 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"abyssal","depthScore":67,"depthScoreParts":{"impact":55,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":5408,"id":"CVE-2026-66012","ts":1788887281039,"field":"exploit_available","old":"false","new":"true"},{"seq":4291,"id":"CVE-2026-66012","ts":1788886395023,"field":"exploit_available","old":"true","new":"false"},{"seq":3040,"id":"CVE-2026-66012","ts":1788883058759,"field":"exploit_available","old":"false","new":"true"},{"seq":2069,"id":"CVE-2026-66012","ts":1788882463497,"field":"exploit_available","old":"true","new":"false"},{"seq":1142,"id":"CVE-2026-66012","ts":1788881899929,"field":"exploit_available","old":"false","new":"true"}]}