SiYuan before v3.7.3 Authentication Bypass via Content Endpoints

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

SiYuan versions before v3.7.3 contain an authentication bypass vulnerability in publish mode where content-returning endpoints getHeadingChildrenDOM, getHeading*Transaction, and getBacklinkDoc perform no password check despite protecting the primary getDoc endpoint. Anonymous attackers can retrieve full content of password-protected documents by obtaining internal block IDs from reader-accessible endpoints and calling unprotected content endpoints to bypass the password gate.

Source published

3 Aug 2026 13:20:36 UTC

Source modified

14 Aug 2026 16:51:06 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

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CVSS 4.0 · 9.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

CVSS 3.1 · 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

SiYuan versions before v3.7.3 contain an authentication bypass vulnerability in publish mode where content-returning endpoints getHeadingChildrenDOM, getHeading*Transaction, and getBacklinkDoc perform no password check despite protecting the primary getDoc endpoint. Anonymous attackers can retrieve full content of password-protected documents by obtaining internal block IDs from reader-accessible endpoints and calling unprotected content endpoints to bypass the password gate.

Source published

3 Aug 2026 14:16:27 UTC

Source modified

23 Oct 2026 21:10:00 UTC

Observed here

25 Oct 2026 15:18:51 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 9.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/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

CVSS 3.1 · [email protected] · Secondary · 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

**CVE:** This vulnerability corresponds to [CVE-2026-68584](https://nvd.nist.gov/vuln/detail/CVE-2026-68584). ### Summary SiYuan'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`). Several 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. ### Details **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. **Content endpoints with no password check (all `CheckAuth`-only):** - `getHeadingChildrenDOM` returns rendered DOM of a heading subtree. - `getHeadingDeleteTransaction`/`getHeadingLevelTransaction`/`getHeadingInsertTransaction` return rendered heading DOM in the computed transaction payload (no mutation occurs on this path). - `getBacklinkDoc`/`getBackmentionDoc` return rendered DOM of referencing blocks. None 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. **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.) **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: 1. `getDoc(protectedDoc)` → returns the password-required placeholder (correctly blocked). 2. `searchEmbedBlock` with a statement selecting heading blocks for the document's root ID → returns the heading IDs (content filtered, IDs retained). 3. `getHeadingChildrenDOM(headingId)` → returns the full rendered body of the protected document, including its protected content. The password gate that step 1 enforces is entirely bypassed by step 3. ### Proof of Concept Reproduced 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`. **1. Confirm the password gate blocks the primary path (anonymous, port 6808):** ``` POST http://127.0.0.1:6808/api/filetree/getDoc {"id":"PROTECTED_DOC"} ``` Returns the password-required placeholder correctly blocked. **2. Leak the protected document's heading ID (anonymous, port 6808):** ``` POST http://127.0.0.1:6808/api/search/searchEmbedBlock {"stmt":"SELECT * FROM blocks WHERE root_id='PROTECTED_DOC' AND type='h'"} ``` Returns heading blocks with their IDs; the content field is filtered but the block ID is retained. **3. Retrieve the protected content without the password (anonymous, port 6808):** ``` POST http://127.0.0.1:6808/api/block/getHeadingChildrenDOM {"id":"HEADING_ID"} ``` Returns HTTP 200 with the rendered body of the protected document, including `TOP_SECRET_CRITICAL_123` retrieved with no token and no password. `getHeadingDeleteTransaction`/`getHeadingLevelTransaction`/`getHeadingInsertTransaction` and `getBacklinkDoc`/ `getBackmentionDoc` provide the same password-free content retrieval given a block ID from the protected document. ### Impact An 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. ### Suggested fix Apply 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.

Source published

3 Sep 2026 21:22:42 UTC

Source modified

10 Sep 2026 15:25:31 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Publisher rating · HIGH

SiYuan: Anonymous publish-password authentication bypass via getHeadingChildrenDOM / getHeading*Transaction / getBacklinkDoc (publish mode) in github.com/siyuan-note/siyuan/kernel

Source published

10 Sep 2026 14:48:42 UTC

Source modified

10 Sep 2026 15:15:13 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.