CVE-2026-73630: SiYuan: authFilePublishAccess distinguishes hidden and forbidden documents from public and nonexistent ones, and issues a publish-auth cookie for documents it reports as forbidden

/api/filetree/authFilePublishAccess is registered with CheckAuth only and is reachable anonymously. It never sets a failure code, so its outcome is signalled entirely by the response message and by whether a Set-Cookie header is present. Those two signals differ across access tiers, which lets an anonymous caller determine, for any candidate document identifier, whether that document is public or nonexistent, password-protected, or exists at the hidden or forbidden tier.

Separately, hidden and forbidden entries carry an empty password. Submitting password:"" therefore satisfies the equality check for them, and the server responds by issuing Set-Cookie: publish-auth-<docID> for a document whose own tier is forbidden.