SiYuan before v3.7.4 Information Disclosure via Block 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 v3.7.4 fail to enforce publish-access checks on getBlockBreadcrumb, getRefText, and getBlockTreeInfos endpoints, allowing disclosure of protected document content and metadata. Anonymous readers or publish RoleReader accounts can retrieve document titles, ancestor block content snippets, reference text, and path metadata for publish-forbidden or password-protected documents by supplying block IDs.

Source published

12 Aug 2026 19:07:49 UTC

Source modified

14 Aug 2026 22:05:17 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

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N

CVSS 3.1 · 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

SiYuan versions before v3.7.4 fail to enforce publish-access checks on getBlockBreadcrumb, getRefText, and getBlockTreeInfos endpoints, allowing disclosure of protected document content and metadata. Anonymous readers or publish RoleReader accounts can retrieve document titles, ancestor block content snippets, reference text, and path metadata for publish-forbidden or password-protected documents by supplying block IDs.

Source published

12 Aug 2026 20:17:52 UTC

Source modified

24 Oct 2026 15:10:00 UTC

Observed here

25 Oct 2026 15:19:03 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 · 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/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 · 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

**CVE:** This vulnerability corresponds to [CVE-2026-72805](https://nvd.nist.gov/vuln/detail/CVE-2026-72805). ### Summary Three block endpoints return document content snippets and metadata without any publish-access check, while their sibling `getBlockInfo` which returns comparable data does enforce one. All three are `CheckAuth`-only, so they are reachable by the publish `RoleReader` token and by the anonymous account when `Publish.Auth.Enable` is `false`. An anonymous reader supplying a block ID receives content and metadata belonging to publish-forbidden and password-protected documents. ### Details `getBlockInfo` (`kernel/api/block.go`) gates on the publish boundary: ```go if !checkBlockPublishAccess(c, id, ret) { return } ``` The following siblings in the same file perform no equivalent check: | Endpoint | Returns | Publish check | |---|---|---| | `getBlockInfo` | root/title/path metadata | `checkBlockPublishAccess`: present | | `getBlockBreadcrumb` | `BlockPath.Name` : root document title plus every ancestor block's content snippet | none | | `getRefText` | the block's reference/anchor text (document content) | none | | `getBlockTreeInfos` | root/title/path metadata for arbitrary block IDs | none | `getBlockBreadcrumb` returns the full ancestor chain including each ancestor block's content snippet, and `getRefText` returns block anchor text both are document content, not just metadata. `getBlockTreeInfos` returns root/title/path for any caller-supplied ID set via `model.GetBlockTreeInfosInBox(...)` with no gate. `getBlockBreadcrumb` and `getRefText` additionally accept a client-supplied notebook argument that routes to the `*InBox` variants, so the same unguarded path applies to encrypted-notebook reads while the notebook is unlocked. The correct primitive already exists in the codebase and is used by `getBlockInfo`; these three handlers simply do not call it. ### Proof of Concept Precondition: publish mode enabled (default port 6808); anonymous when `Publish.Auth.Enable` is `false`, otherwise any publish reader account. A document `D` is marked publish-forbidden (or password-protected) and contains a block `BLOCK_ID` under a heading with distinctive content. **Control: the gated sibling correctly refuses:** ``` POST http://127.0.0.1:6808/api/block/getBlockInfo {"id":"BLOCK_ID"} ``` Blocked by `checkBlockPublishAccess`. **Disclosure: the ungated siblings return the data anyway:** ``` POST http://127.0.0.1:6808/api/block/getBlockBreadcrumb {"id":"BLOCK_ID"} → ancestor chain including the forbidden document's title and ancestor block content snippets POST http://127.0.0.1:6808/api/block/getRefText {"id":"BLOCK_ID"} → the block's reference/anchor text (content of the forbidden document) POST http://127.0.0.1:6808/api/block/getBlockTreeInfos {"ids":["BLOCK_ID"]} → root ID, title, and path for the forbidden document ``` Verified by code inspection at `origin/master` (`eef10568`): `getBlockInfo` contains the `checkBlockPublishAccess` call; `getBlockBreadcrumb`, `getRefText`, and `getBlockTreeInfos` contain no publish-access, publish-ignore, or readonly-role check in their bodies. ### Impact An anonymous reader (publish mode with auth disabled) or any publish `RoleReader` can read, for documents explicitly excluded from publishing or protected by a publish password: - the document title and full ancestor chain, including ancestor block content snippets (`getBlockBreadcrumb`); - block reference/anchor text, i.e. document content (`getRefText`); - root ID, title, and path metadata for arbitrary block IDs (`getBlockTreeInfos`). Because `getBlockBreadcrumb` and `getRefText` accept a notebook argument routing to the `*InBox` variants, the same disclosure applies to encrypted notebooks while unlocked. Confidentiality-only; the precondition is a block ID, obtainable from other reader-reachable endpoints. ### Suggested fix Call `checkBlockPublishAccess` (as `getBlockInfo` does) in `getBlockBreadcrumb`, `getRefText`, and `getBlockTreeInfos` before returning data for `getBlockTreeInfos`, apply it per ID and drop unauthorized entries. Confirm the `*InBox` variants (`GetBlockRefTextInBox`, `BuildBlockBreadcrumbInBox`) enforce the same boundary so the notebook-argument path is covered.

Source published

3 Sep 2026 22:52:12 UTC

Source modified

10 Sep 2026 15:25:36 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:L/I:N/A:N

Publisher rating · MODERATE

SiYuan: Missing publish-access check on getBlockBreadcrumb, getRefText, and getBlockTreeInfos discloses content and metadata of protected/forbidden documents in github.com/siyuan-note/siyuan/kernel

Source published

10 Sep 2026 14:48:42 UTC

Source modified

10 Sep 2026 15:15:14 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.