SiYuan: Publish-boundary bypass via WebSocket broadcast: anonymous readers receive a live unfiltered feed of all edits including protected/forbidden documents (publish mode)

CVE: This vulnerability corresponds to CVE-2026-72810.

Summary

WebSocket sessions established through the publish surface (port 6808, RoleReader anonymous when Publish.Auth.Enable is false) are added to the same broadcast session pool as authenticated sessions. The kernel's broadcast functions push content events transactions carrying block DOM, document save/create, move/rename to every session in the pool with no role or publish-access filtering. As a result, an anonymous reader who holds a WebSocket connection open passively receives a real-time feed of every edit made in the workspace, including edits to password-protected, publish-forbidden, and unpublished documents. Because these events are delivered over the push channel and never pass through an HTTP handler, none of the publish-access filters that gate the HTTP endpoints apply.

Details

Session admission. HandleConnect admits the injected RoleReader publish token, and the session is registered via AddPushChan into the same sessions pool used for authenticated clients.

Unfiltered broadcast. The broadcast functions (Broadcast, broadcastOthers, broadcastOtherAppMains, …) write to every session in the pool with no role or publish-access check. The isPublish flag on a session is consulted only to send the "service closed" notice it is never used to gate content. Content events are pushed via PushModeBroadcast → Broadcast(), so transactions (with rendered block DOM), savedoc/create, and moveDoc/rename events reach the publish reader's socket unfiltered.

No HTTP filter applies. This is a push channel, the events originate from the kernel's own edit pipeline and are broadcast directly to open sockets. They never traverse an HTTP handler, so the publish-access filters that gate the HTTP content endpoints (and the incomplete/missing filters reported separately on those endpoints) are not in the path at all. The WebSocket route (/ws) is CheckAuth-only, which the publish RoleReader token satisfies.

Proof of Concept

Reproduced on a local instance (SiYuan running locally, publish mode enabled on port 6808, publish Basic Auth disabled). An anonymous client (no token, no password) opens wss://127.0.0.1:6808/ws and holds it open while an administrator edits documents in the workspace.

The anonymous socket received, in real time and unfiltered:

• updateAttrs with name=WS_LEAK_SECRET_9931 on a block whose rootID is a password-protected document.
• The secret title WS_SECRET_DOC_7742 of a newly created document.
• The create event carrying the notebook (box) name CritChain and the document path.

No HTTP request was made beyond the WebSocket upgrade; the content arrived over the push channel.

Impact

An anonymous reader (publish mode with auth disabled) or any publish RoleReader who merely holds a WebSocket connection open receives a live feed of every edit an administrator makes: block DOM, attributes, titles, notebook names, and document structure, including for password-protected, publish-forbidden, and unpublished documents. This defeats the publish-access and publish-password boundaries entirely for any content edited while the socket is open. The precondition is trivial: an administrator active in the workspace while the anonymous socket is connected. Confidentiality-only (passive disclosure); the channel is receive-only for the reader. Encrypted-notebook content follows the same broadcast path if edited while unlocked.

Suggested fix

Filter broadcasts by session before writing: for any session flagged isPublish, apply the same publish-access/publish-ignore/publish-password checks used on the HTTP content path before pushing a content event, or exclude publish sessions from content broadcasts entirely and deliver only the events a publish viewer is authorized to see. The isPublish flag is already present on the session; it should gate content, not only the service-closed notice.