Vulnerability-Lookup

CVE-2026-66012 (GCVE-0-2026-66012)

Vulnerability from cvelistv5 – Published: 2026-07-25 10:45 – Updated: 2026-07-25 10:45

Title

SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP

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, 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.

Severity

10 (Critical)


                        
                          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

10 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CWE

CWE-862 - Missing Authorization

Assigner

VulnCheck

References

3 references

URL	Tags
https://github.com/siyuan-note/siyuan/security/ad…	vendor-advisory
https://github.com/siyuan-note/siyuan/commit/c72c…	patch
https://www.vulncheck.com/advisories/siyuan-befor…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
siyuan-note	siyuan	Affected: 0 , < 3.7.2 (semver) Unaffected: 3.7.2 (semver)

Date Public

2026-07-13 00:00

Credits

hypnguyen1209

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/github.com/siyuan-note/siyuan",
          "product": "siyuan",
          "vendor": "siyuan-note",
          "versions": [
            {
              "lessThan": "3.7.2",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "3.7.2",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "hypnguyen1209"
        }
      ],
      "datePublic": "2026-07-13T00:00:00.000Z",
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 10,
            "baseSeverity": "CRITICAL",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "HIGH",
            "subIntegrityImpact": "HIGH",
            "userInteraction": "NONE",
            "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 10,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-862",
              "description": "Missing Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-25T10:45:56.085Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-cvhv-7xhj-xjp8)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cvhv-7xhj-xjp8"
        },
        {
          "name": "https://github.com/siyuan-note/siyuan/commit/c72ca4cd09019e5f64afdee8f8c6ec5ef34858db",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/siyuan-note/siyuan/commit/c72ca4cd09019e5f64afdee8f8c6ec5ef34858db"
        },
        {
          "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"
        }
      ],
      "title": "SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-66012",
    "datePublished": "2026-07-25T10:45:56.085Z",
    "dateReserved": "2026-07-23T19:22:30.643Z",
    "dateUpdated": "2026-07-25T10:45:56.085Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-66012\",\"sourceIdentifier\":\"disclosure@vulncheck.com\",\"published\":\"2026-07-25T11:17:19.053\",\"lastModified\":\"2026-07-25T11:17:19.053\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"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.\"}],\"affected\":[{\"source\":\"disclosure@vulncheck.com\",\"affectedData\":[{\"vendor\":\"siyuan-note\",\"product\":\"siyuan\",\"defaultStatus\":\"unaffected\",\"packageURL\":\"pkg:npm/github.com/siyuan-note/siyuan\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"3.7.2\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"3.7.2\",\"versionType\":\"semver\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"disclosure@vulncheck.com\",\"type\":\"Secondary\",\"cvssData\":{\"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X\",\"baseScore\":10.0,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"HIGH\",\"vulnIntegrityImpact\":\"HIGH\",\"vulnAvailabilityImpact\":\"HIGH\",\"subConfidentialityImpact\":\"HIGH\",\"subIntegrityImpact\":\"HIGH\",\"subAvailabilityImpact\":\"HIGH\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"cvssMetricV31\":[{\"source\":\"disclosure@vulncheck.com\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H\",\"baseScore\":10.0,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":6.0}]},\"weaknesses\":[{\"source\":\"disclosure@vulncheck.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-862\"}]}],\"references\":[{\"url\":\"https://github.com/siyuan-note/siyuan/commit/c72ca4cd09019e5f64afdee8f8c6ec5ef34858db\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cvhv-7xhj-xjp8\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://www.vulncheck.com/advisories/siyuan-before-unauthenticated-administrator-takeover-via-mcp\",\"source\":\"disclosure@vulncheck.com\"}]}}"
  }
}

GHSA-HP8G-G2QJ-WGPJ

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31

Details

Severity

10.0 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

10.0 (Critical)


                  
                    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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-66012"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-862"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T11:17:19Z",
    "severity": "CRITICAL"
  },
  "details": "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.",
  "id": "GHSA-hp8g-g2qj-wgpj",
  "modified": "2026-07-25T12:31:39Z",
  "published": "2026-07-25T12:31:39Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cvhv-7xhj-xjp8"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66012"
    },
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/commit/c72ca4cd09019e5f64afdee8f8c6ec5ef34858db"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/siyuan-before-unauthenticated-administrator-takeover-via-mcp"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-66012 (GCVE-0-2026-66012)

GHSA-HP8G-G2QJ-WGPJ

Tags

Sightings

Nomenclature