Executive brief
SiYuan is a note-taking and documentation application. A flaw in the publication access control allows anonymous users to retrieve fully decrypted content from encrypted notebooks while they are unlocked by the legitimate owner, without requiring any authentication, encryption keys, or passwords. An attacker simply needs to know the notebook ID and document IDs to access sensitive information that the owner believed was encrypted and protected.
Technical details
The vulnerability is a missing authorization check (CWE-862) in the publish-access gate. The publish access control uses an opt-out list (publishAccess.json) that is written only by administrative functions; the encryption subsystem never writes to it. Consequently, encrypted notebooks are never listed in the access-control file and are treated as publicly accessible by default. When an encrypted notebook is unlocked by the legitimate user, the authorization layer (checkBlockTreeAccessableByPublishAccess) lacks any check for encryption status and returns true for all unlisted boxes. An unauthenticated attacker can call lsNotebooks to enumerate encrypted notebooks, listDocsByPath to discover documents within them, and getDoc/getBlockKramdown to retrieve fully decrypted content. No key material, password, or cracking is required; the kernel automatically decrypts data because the authorization layer never queries encryption status. The exposure is bounded to the window when the notebook is unlocked by the legitimate user.
Affected products
- SiYuan SiYuan < 3.7.4
Timeline
- 2026-08-12: disclosed
- 2026-07-26: patched: v3.7.4 released (primary advisory GHSA-v684-q882-jgmq published 2026-07-26)
- 2026-09-08: other: This advisory (GHSA-xx34-6cjg-prh8) withdrawn as duplicate