CVE-2026-68584: SiYuan Authentication Bypass Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7j72-f6wg-cxw6",
  "modified" : "2026-09-08T18:03:33Z",
  "published" : "2026-09-03T21:22:42Z",
  "aliases" : [ "CVE-2026-68584" ],
  "summary" : "SiYuan: Anonymous publish-password authentication bypass via getHeadingChildrenDOM / getHeading*Transaction / getBacklinkDoc (publish mode)",
  "details" : "**CVE:** This vulnerability corresponds to [CVE-2026-68584](https://nvd.nist.gov/vuln/detail/CVE-2026-68584).\n\n### Summary\n\nSiYuan's publish mode defines a \"protected\" access level: a document that is publicly listed but requires a password to read (per the product's own UI help text, protected = \"Publicly visible, requires password to access\"). The password is enforced on the primary content path (`getDoc`, via `FilterContentByPublishAccess`).\n\nSeveral other content-returning endpoints `getHeadingChildrenDOM`, `getHeadingDeleteTransaction`/`getHeadingLevelTransaction`/ `getHeadingInsertTransaction`, and `getBacklinkDoc`/`getBackmentionDoc` return rendered block DOM with **no password check at all**. Combined with reader-reachable endpoints that leak a protected document's internal block IDs, an anonymous reader can retrieve the full body of a password-protected document without the password. This has been reproduced end-to-end on a live instance.\n\n### Details\n\n**The password control and where it is enforced.** Publish access has five levels encoded in `visible`/`password`/`disable`: public, protected (password), hidden, private (password), forbidden. `getDoc` correctly enforces the password for protected/private documents via `FilterContentByPublishAccess`. The bug is that other content endpoints do not.\n\n**Content endpoints with no password check (all `CheckAuth`-only):**\n- `getHeadingChildrenDOM` returns rendered DOM of a heading subtree.\n- `getHeadingDeleteTransaction`/`getHeadingLevelTransaction`/`getHeadingInsertTransaction` return rendered heading DOM in the computed transaction payload (no mutation occurs on this path).\n- `getBacklinkDoc`/`getBackmentionDoc` return rendered DOM of referencing blocks.\n\nNone of these invokes the publish-password check that `getDoc` applies. Each converts a block ID into full rendered content regardless of the containing document's protected/password status.\n\n**The ID-leak that removes the precondition.** A protected document is, by design, publicly listed (`listDocsByPath` filters on `visible`, and protected documents are visible), so an anonymous reader obtains the document's root ID. The document's internal block/heading IDs are then obtainable from reader-reachable endpoints notably the `searchEmbedBlock` endpoint (reported separately), whose post-query filter `FilterEmbedBlocksByPublishAccess` **replaces the content string but retains the block ID**. So the \"filtered\" search still yields the protected document's internal heading IDs. (Other reader-reachable endpoints also leak block IDs, the vulnerability does not depend on any single ID source.)\n\n**The chain, reproduced on a live instance.** Against a real protected document (password set), an anonymous reader on port 6808 with no token and no password:\n\n1. `getDoc(protectedDoc)` → returns the password-required placeholder (correctly blocked).\n2. `searchEmbedBlock` with a statement selecting heading blocks for the document's root ID → returns the heading IDs (content filtered, IDs retained).\n3. `getHeadingChildrenDOM(headingId)` → returns the full rendered body of the protected document, including its protected content.\n\nThe password gate that step 1 enforces is entirely bypassed by step 3.\n\n### Proof of Concept\n\nReproduced on a local instance (SiYuan running locally, publish mode enabled on port 6808, publish Basic Auth disabled). Setup: a document marked \"protected\" with password, whose body contains the unique marker `TOP_SECRET_CRITICAL_123`.\n\n**1. Confirm the password gate blocks the primary path (anonymous, port 6808):**\n```\nPOST http://127.0.0.1:6808/api/filetree/getDoc\n{\"id\":\"PROTECTED_DOC\"}\n```\nReturns the password-required placeholder correctly blocked.\n\n**2. Leak the protected document's heading ID (anonymous, port 6808):**\n```\nPOST http://127.0.0.1:6808/api/search/searchEmbedBlock\n{\"stmt\":\"SELECT * FROM blocks WHERE root_id='PROTECTED_DOC' AND type='h'\"}\n```\nReturns heading blocks with their IDs; the content field is filtered but the block ID is retained.\n\n**3. Retrieve the protected content without the password (anonymous, port 6808):**\n```\nPOST http://127.0.0.1:6808/api/block/getHeadingChildrenDOM\n{\"id\":\"HEADING_ID\"}\n```\nReturns HTTP 200 with the rendered body of the protected document, including `TOP_SECRET_CRITICAL_123` retrieved with no token and no password.\n\n`getHeadingDeleteTransaction`/`getHeadingLevelTransaction`/`getHeadingInsertTransaction` and `getBacklinkDoc`/ `getBackmentionDoc` provide the same password-free content retrieval given a block ID from the protected document.\n\n### Impact\n\nAn anonymous reader (publish mode with auth disabled) or any publish `RoleReader` can read the full content of a password-protected published document without the password, defeating the \"protected\" access control the product documents as a password gate. The core defect is that these content-returning endpoints perform no publish-password check; the ID-leak endpoints (multiple sources) supply the block IDs that make the bypass reachable anonymously and untargeted. Impact is confidentiality-only (content disclosure); no modification occurs on these paths. Encrypted notebooks are out of scope.\n\n### Suggested fix\n\nApply the publish-password/publish-access check that `getDoc` uses (`FilterContentByPublishAccess`/`IsReadOnlyRoleContext` plus the password-cookie check) to every content-returning endpoint: `getHeadingChildrenDOM`, the three `getHeading*Transaction` handlers, and `getBacklinkDoc`/`getBackmentionDoc`. Separately, `FilterEmbedBlocksByPublishAccess` should omit filtered blocks entirely rather than blanking the content while retaining the ID, so that filtered results cannot be used to enumerate a protected document's internal block IDs. The durable fix is to enforce the publish boundary in the shared render/DOM path rather than per-handler, since any content endpoint that omits the check reintroduces this class.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/siyuan-note/siyuan/kernel"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.0.0-20260721020826-2d069dce84a2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7j72-f6wg-cxw6"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-68584"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/siyuan-note/siyuan/commit/2d069dce84a25c959ef0093c72c98e05778ef218"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/siyuan-note/siyuan"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-content-endpoints"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-288" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-03T21:22:42Z",
    "nvd_published_at" : null
  }
}