{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:golang/github.com/siyuan-note/siyuan/kernel",
          "product": "siyuan",
          "vendor": "siyuan-note",
          "versions": [
            {
              "lessThan": "3.7.4",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "3.7.4",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "disclosure@vulncheck.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "SiYuan versions \u003c= v3.7.2 (patched in v3.7.4) contain an authentication bypass vulnerability in the kernel\u0027s CheckAuth function, which grants the administrator role (RoleAdministrator) to any request whose RemoteAddr is loopback (127.0.0.1) for a specific set of endpoints (including /api/system/exit, getNetwork, getWorkspaceInfo, /assets/*, and /export/*). These localhost bypasses sit outside the access auth code gate, so they apply even when an access auth code is configured. Because the fixed-port reverse proxy forwards requests to the kernel over loopback without injecting an authentication token and does not configure trusted proxies, a request forwarded through this proxy reaches the kernel with RemoteAddr = 127.0.0.1. If the fixed-port proxy is bound to a network interface, this could allow a remote unauthenticated attacker to obtain admin access on the affected endpoints; however, per the advisory this remote forwarding behavior was established only by code inspection and was not reproduced end-to-end."
    }
  ],
  "id": "CVE-2026-72809",
  "lastModified": "2026-08-26T16:56:50.830",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.0,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.5,
        "impactScore": 5.5,
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "LOCAL",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 7.1,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:H/SC:N/SI:N/SA:N/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-72809",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-14T22:06:55.491557Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-12T20:17:53.110",
  "references": [
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3mp7-4rh5-jrv9"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-localhost-trust"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3mp7-4rh5-jrv9"
    }
  ],
  "sourceIdentifier": "disclosure@vulncheck.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-290"
        }
      ],
      "source": "disclosure@vulncheck.com",
      "type": "Secondary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/siyuan-note/siyuan/kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.0-20260723031701-9c16e9851f0b"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-72809"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-290"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-03T22:34:06Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "**CVE:** This vulnerability corresponds to [CVE-2026-72809](https://nvd.nist.gov/vuln/detail/CVE-2026-72809).\n\n### Summary\n\nThe kernel\u0027s `CheckAuth` grants `RoleAdministrator` to any request whose `RemoteAddr` is loopback (`127.0.0.1`), for a specific set of endpoints, and these localhost bypasses sit **outside** the `accessAuthCode` gate so they apply even when an access auth code is configured. This is demonstrated live (Part A below).\n\nSeparately, the fixed-port reverse proxy (`fixedport.go`) forwards requests to the kernel over loopback and injects no authentication token, and no `SetTrustedProxies` is configured, so gin does not derive the client address from forwarding headers. By code inspection, a request forwarded through this proxy would reach the kernel with `RemoteAddr = 127.0.0.1`. **If** the fixed-port proxy is bound to a network interface (via `NetworkServe`) and forwards remote requests to the kernel this way, the localhost bypass would grant a remote unauthenticated caller admin on those endpoints. This second step is established by reading the code but was **not reproduced end-to-end**, and I\u0027m asking the maintainer to confirm the proxy\u0027s runtime forwarding behavior (Part B below).\n\n### Details\n\n**Localhost-trust admin bypass (proven).** `CheckAuth` (`session.go:298-321`) contains localhost-only bypasses that key off `RemoteAddr` and grant `RoleAdministrator`. They sit outside the `accessAuthCode` gate i.e. they apply even when an access auth code is set and cover `/api/system/exit`, `getNetwork`, `getWorkspaceInfo`, `/assets/*`, and `/export/*`.\n\n**Fixed-port proxy behavior (code inspection).** `fixedport.go` is a plain reverse proxy that dials the kernel at `127.0.0.1` and injects no token unlike the publish proxy, which injects a `RoleReader` JWT. There is no `SetTrustedProxies` call, so gin does not rewrite `RemoteAddr` from `X-Forwarded-For`. On this reading, a request forwarded through the fixed-port proxy reaches the kernel with `RemoteAddr = 127.0.0.1`.\n\n**The composition (conditional).** If both hold at runtime, then: remote request \u2192 fixed-port proxy on a network interface \u2192 forwarded to kernel at `127.0.0.1` (no token) \u2192 kernel sees `RemoteAddr = 127.0.0.1` \u2192 localhost bypass grants admin for the endpoints above. I have proven the final link (localhost \u2192 admin) and read the code for the forwarding link, but have not confirmed at runtime that the fixed-port proxy is instantiated and forwards remote requests as loopback in a shipped configuration.\n\n**Distinct from the previously-dismissed localhost\u2192admin observation.** That observation concerned the *publish* proxy path, where the injected `RoleReader` JWT causes `CheckAuth` to early-return before reaching the localhost bypasses. The fixed-port proxy injects no token, so a request through it would fall through to the `RemoteAddr`-keyed bypass instead. Different proxy, different code path.\n\n### Proof of Concept\n\n**Part A: the localhost bypass grants admin without auth, outside the auth-code gate (demonstrated live).**\nOn a local instance with an access auth code configured, the same no-token `getWorkspaceInfo` request returns different results depending on the source address the kernel sees:\n- From a non-loopback source (kernel sees a non-127.0.0.1 address): `HTTP 401`.\n- From `127.0.0.1` (kernel sees loopback): `{\"code\":0,\"data\":{\"workspaceDir\":\"/siyuan/workspace\",\u2026}}` admin data, no auth, despite `accessAuthCode` being set.\n\nThis confirms the localhost-trust bypass grants admin for these endpoints and is not gated by the access auth code.\n\n**Part B: remote \u2192 proxy \u2192 loopback (code inspection only; NOT reproduced).**\nBy reading `fixedport.go`, the proxy dials `127.0.0.1`, injects no token, and no `SetTrustedProxies` is set. I was not able to reproduce this end-to-end: the `serve` CLI in the container image tested exposes only `--port` and `--accessAuthCode`, not a flag that instantiates the fixed-port proxy in the `NetworkServe`-on-a-non-default-port shape, so the remote\u2192proxy\u2192loopback chain was not exercised at runtime. I did not invoke the destructive `/api/system/exit` endpoint. **I\u0027m asking the maintainer to confirm: under what conditions is the fixed-port proxy instantiated, does it bind a non-loopback interface under `NetworkServe`, and does it forward to the kernel preserving the client address or as loopback?** That determines whether Part A\u0027s bypass is remotely reachable.\n\n### Impact\n\n**Confirmed (Part A):** on any deployment where a caller can cause the kernel to see a loopback `RemoteAddr`, the endpoints `/api/system/exit`, `getNetwork`, `getWorkspaceInfo`, `/assets/*`, and `/export/*` are reachable with admin rights without the access auth code i.e. the auth code does not protect these endpoints against a loopback-sourced caller. On its own this is a local/adjacent bypass of the access-code control for those endpoints. If the fixed-port proxy forwards remote requests to the kernel as loopback (to be confirmed by the maintainer), a *remote* unauthenticated attacker obtains those admin capabilities, remote kernel shutdown (DoS), network/workspace-path disclosure, and admin-level asset/export reads that bypass the publish-access filter. This would be a remote authentication bypass. It does not grant the full admin API only the localhost-trusted endpoints.\n\n### Suggested fix\n\nDo not derive admin trust from `RemoteAddr` when a proxy forwards over loopback. Options: have the fixed-port proxy inject an explicit role/token (as the publish proxy does) so the kernel authorizes on the claim rather than the source address; or configure `SetTrustedProxies` and derive the real client address before applying any localhost bypass; or require the access auth code for these endpoints regardless of source address. The localhost bypass assumes loopback implies a local trusted caller, any loopback-dialing proxy breaks that assumption.",
  "id": "GHSA-3mp7-4rh5-jrv9",
  "modified": "2026-09-03T22:34:06Z",
  "published": "2026-09-03T22:34:06Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3mp7-4rh5-jrv9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72809"
    },
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/commit/9c16e9851f0b5d7ed179e5c2fca15a7724666871"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/siyuan-note/siyuan"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-localhost-trust"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "SiYuan: Localhost-trust admin bypass on auth-code-gated endpoints, with potential remote reachability via the fixed-port proxy"
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 3.7.4"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/siyuan-note/siyuan/kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-290"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-03T22:32:26Z",
    "nvd_published_at": "2026-08-12T20:17:53Z",
    "severity": "HIGH"
  },
  "details": "## Duplicate Advisory\n\nThis advisory has been withdrawn because it is a duplicate of\u00a0GHSA-3mp7-4rh5-jrv9. This link is maintained to preserve external references.\n\n## Original Description\nSiYuan versions \u003c= v3.7.2 (patched in v3.7.4) contain an authentication bypass vulnerability in the kernel\u0027s CheckAuth function, which grants the administrator role (RoleAdministrator) to any request whose RemoteAddr is loopback (127.0.0.1) for a specific set of endpoints (including /api/system/exit, getNetwork, getWorkspaceInfo, /assets/*, and /export/*). These localhost bypasses sit outside the access auth code gate, so they apply even when an access auth code is configured. Because the fixed-port reverse proxy forwards requests to the kernel over loopback without injecting an authentication token and does not configure trusted proxies, a request forwarded through this proxy reaches the kernel with RemoteAddr = 127.0.0.1. If the fixed-port proxy is bound to a network interface, this could allow a remote unauthenticated attacker to obtain admin access on the affected endpoints; however, per the advisory this remote forwarding behavior was established only by code inspection and was not reproduced end-to-end.",
  "id": "GHSA-8wx9-j7j5-h9vp",
  "modified": "2026-09-03T22:32:26Z",
  "published": "2026-08-12T21:31:42Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3mp7-4rh5-jrv9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72809"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-localhost-trust"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:H/SC:N/SI:N/SA:N/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"
    }
  ],
  "summary": "Duplicate Advisory: Localhost-trust admin bypass on auth-code-gated endpoints, with potential remote reachability via the fixed-port prox",
  "withdrawn": "2026-09-03T22:32:26Z"
}