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SiYuan: Anonymous publish-password authentication bypass via getHeadingChildrenDOM / getHeading*Transaction / getBacklinkDoc (publish mode)

High severity GitHub Reviewed Published Jul 21, 2026 in siyuan-note/siyuan

Package

gomod github.com/siyuan-note/siyuan/kernel (Go)

Affected versions

< 0.0.0-20260721020826-2d069dce84a2

Patched versions

0.0.0-20260721020826-2d069dce84a2

Description

CVE: This vulnerability corresponds to 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.

References

@88250 88250 published to siyuan-note/siyuan Jul 21, 2026
Published to the GitHub Advisory Database Sep 3, 2026
Reviewed Sep 3, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

EPSS score

Weaknesses

Authentication Bypass Using an Alternate Path or Channel

The product requires authentication, but the product has an alternate path or channel that does not require authentication. Learn more on MITRE.

CVE ID

No known CVE

GHSA ID

GHSA-7j72-f6wg-cxw6

Source code

Credits

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