CVE-2026-68584

SiYuan's publish mode supports a 'protected' access level in which a document is publicly listed but requires a password to read, yet the password check (FilterContentByPublishAccess) is only enforced on the primary getDoc content path. Several sibling endpoints — getHeadingChildrenDOM, the getHeadingDeleteTransaction/getHeadingLevelTransaction/getHeadingInsertTransaction endpoints, and getBacklinkDoc/getBackmentionDoc — return full rendered block DOM with no password check at all. Because anonymous readers can also obtain a protected document's internal block and heading IDs from reader-reachable endpoints (e.g., searchEmbedBlock, which strips protected content but retains block IDs), chaining an ID leak with any of these unauthenticated content endpoints yields the complete body of a password-protected document without the password. Any SiYuan instance running publish mode with password-protected documents exposed to anonymous readers is affected; the chain was reproduced end-to-end against a live instance. No public PoC or in-the-wild exploitation is currently known, and EPSS estimates roughly a 0.3% chance of exploitation in the next 30 days.

What to do: Inventory internet-exposed SiYuan publish endpoints (default port 6808) for documents configured as 'protected' and treat their contents as readable without the password until patched. Since no fixed version is stated in the available data, mitigate by unpublishing password-protected documents or fronting the publish service with reverse-proxy authentication/network access restrictions, and monitor the SiYuan project for a release that applies the publish-password filter to the heading and backlink endpoints.