CVE-2026-68587: SiYuan: missing authz exposes publish-disabled docs

**CVE:** This vulnerability corresponds to [CVE-2026-68587](https://nvd.nist.gov/vuln/detail/CVE-2026-68587). ### Summary Three "heading transaction" endpoints `/api/block/getHeadingDeleteTransaction`, `/api/block/getHeadingLevelTransaction`, and `/api/block/getHeadingInsertTransaction` return the rendered block DOM of a heading and its subtree in the computed transaction payload, with no publish-access check. They are gated by `CheckAuth` only, so they are reachable by the publish `RoleReader` token, and by the anonymous account when `Publish.Auth.Enable` is `false`. Despite their write-implying names, these endpoints perform no mutation on this path, they compute a transaction object and return it, and that object contains `RenderNodeBlockDOM` output. As a result, an anonymous reader who supplies a heading block ID can read the full rendered content of a document that has been explicitly marked publish-disabled by an administrator, content that the reader-facing `/api/filetree/getDoc` path correctly refuses to return. ### Details **Route / auth tier.** All three routes are registered `CheckAuth`-only (no `CheckAdminRole`). `CheckAuth` admits `RoleReader`, and the publish proxy forwards port-6808 traffic with a Reader JWT (anonymous account when publish auth is disabled). Anonymous/reader reachable. **No publish-access filter.** `GetHeadingDeleteTransaction` / `GetHeadingLevelTransaction` / `GetHeadingInsertTransaction` load the heading's block tree and render its DOM into the returned transaction's operation data. None of the three invokes `IsReadOnlyRoleContext` / the publish-access filter that the reader-safe content path (`getDoc`) applies. The reader-facing content endpoints (`getDoc`, and the `CheckAdminRole`-gated `getBlockDOM`/`getBlockKramdown`) treat rendered block DOM as gated content; these three transaction endpoints return the same rendered DOM without that gate. **Write-implying name, read behavior.** On this code path the endpoints only *compute* the transaction (e.g. the `undoOperations` a delete would produce) and return it; nothing is deleted or modified. The returned operation data includes the rendered HTML of the heading subtree. This mismatch, mutation-shaped name, content-returning behavior is why the gap is easy to miss. ### Proof of Concept Reproduced on a local instance (SiYuan running locally, publish mode enabled on port 6808, publish Basic Auth disabled). `DOC` is a document containing a heading `HEADING` whose body contains the unique marker `UNIQUE_MARKER_99`, and `DOC` is marked publish-disabled by the administrator. **1. Confirm the document is publish-disabled (admin action, the boundary that should block reads):** ``` POST http://127.0.0.1:6806/api/filetree/setPublishAccess Authorization: Token <admin-token> {"id":"DOC","visible":false,"password":"","disable":true} ``` **2. Baseline: the reader-safe content path correctly blocks it (anonymous, port 6808):** ``` POST http://127.0.0.1:6808/api/filetree/getDoc {"id":"DOC"} ``` Returns the blocked/placeholder response, the publish filter is applied, no content. **3. Disclosure: the transaction endpoint returns the content (anonymous, port 6808):** ``` POST http://127.0.0.1:6808/api/block/getHeadingDeleteTransaction {"id":"HEADING"} ``` Returns HTTP 200; `data.undoOperations[].data` contains the rendered HTML of the heading subtree, including the hidden body text `UNIQUE_MARKER_99`. Nothing is deleted — the endpoint only computes the transaction. This is the full content of a publish-disabled document returned to an anonymous reader. **4. Sibling endpoints: same disclosure, same input:** ``` POST http://127.0.0.1:6808/api/block/getHeadingLevelTransaction {"id":"HEADING","level":2} POST http://127.0.0.1:6808/api/block/getHeadingInsertTransaction {"id":"HEADING"} ``` Both return the rendered DOM of the heading subtree in their operation data. ### Impact An anonymous reader (publish mode with auth disabled) or any publish `RoleReader` who supplies a heading block ID can read the full rendered content of a publish-disabled document, defeating a boundary the administrator explicitly configured. **Precondition:** the request requires the target heading's block ID. Block IDs are high-entropy and are not returned by this endpoint, so this endpoint alone does not permit untargeted enumeration of arbitrary documents. However, block/heading IDs for publish-disabled documents are obtainable from other `CheckAuth`-only endpoints that lack the publish-access filter (the publish-boundary handler set reported separately, e.g. `getHeadingChildrenIDs`). Chained with such an ID source, this yields end-to-end unauthenticated full-content disclosure of publish-disabled documents. Presented standalone, the attacker must already possess the heading ID. Impact is confidentiality-only: these endpoints return content but do not (on this path) modify data. No admin role, CSRF token, or write permission is required. Encrypted notebooks are out of scope. ### Suggested fix Apply the same publish-access check the content path uses `IsReadOnlyRoleContext` / the publish-access filter used by `getDoc` to all three `getHeading*Transaction` handlers, or gate them behind `CheckAdminRole` consistent with `getBlockDOM`/`getBlockKramdown`. Any endpoint that returns rendered block DOM should enforce the same publish boundary as the primary content path.

An attacker locates an internet-facing SiYuan instance running in publish mode with authentication disabled (common in self-hosted 'share my notes publicly' setups). Using a separately-disclosed information-leak endpoint (getHeadingChildrenIDs) that also lacks the publish-access filter, the attacker enumerates heading block IDs belonging to a document the owner explicitly marked as publish-disabled — for example, a draft containing credentials, internal roadmap notes, or confidential research pulled into a personal knowledge base feeding an AI assistant. The attacker then sends an anonymous POST to /api/block/getHeadingDeleteTransaction with that block ID. The server computes what a delete operation would look like, embeds the fully rendered HTML of the heading and its subtree in the response, and returns HTTP 200 without deleting anything. The attacker extracts the hidden content directly from the JSON response, fully bypassing the publish-access boundary the document owner configured, with no authentication, no CSRF token, and no trace beyond a routine-looking API call.