Description

SiYuan before v3.7.4 contains an information disclosure vulnerability in the /api/notebook/getNotebookInfo endpoint that returns notebook metadata without authorization checks. Attackers can read notebook names, document counts, sizes, and timestamps for closed or non-published notebooks that should be hidden from readers.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.8",
  "pubDate": "2026-08-12T20:17:50.407Z",
  "pubdate": "2026-08-12T20:17:50.407Z",
  "executiveSummary": "An information disclosure vulnerability has been identified in SiYuan prior to v3.7.4, specifically residing within the /api/notebook/getNotebookInfo endpoint. This security flaw allows unauthenticated or unauthorized remote actors to bypass access control mechanisms and retrieve sensitive metadata associated with closed or non-published notebooks. The compromised data elements include internal notebook names, document counts, storage sizes, and precise timestamps, which are strictly intended to be hidden from unauthorized readers.\nThe risk implications of this vulnerability center on unauthorized reconnaissance and data exposure. By querying the affected API route directly, an external attacker can systematically harvest structural intelligence regarding private workspaces within the deployment. This intelligence facilitates further targeted attacks against the underlying architecture. Exploitation requires network access to the target SiYuan instance and the ability to issue HTTP requests to the vulnerable endpoint, with no prior authentication or administrative privileges required.",
  "technicalDetails": "The root cause of the vulnerability stems from an absolute lack of authorization checks and session validation within the request handling logic of the /api/notebook/getNotebookInfo endpoint. In secure application architectures, API endpoints responsible for retrieving resource metadata must enforce strict access control lists (ACLs) to verify that the requesting entity possesses sufficient privileges to access the targeted resource. In the affected versions of SiYuan, the application processes incoming requests to the vulnerable component without verifying whether the user is authenticated or authorized to view closed or unpublished notebooks.\nThe vulnerable component is the server-side API routing and controller logic handling notebook metadata retrieval. Affected versions comprise all instances of SiYuan prior to v3.7.4. The exploitation method involves an attacker crafting an arbitrary HTTP request directed at the /api/notebook/getNotebookInfo endpoint. Because the endpoint fails to parse and validate authorization tokens or session cookies against the requested notebook identifier, the server processes the request unconditionally.\nThe attack flow proceeds as follows: First, the adversary identifies a target running a vulnerable SiYuan instance exposed to the network. Second, the attacker formulates an HTTP request targeted at /api/notebook/getNotebookInfo, potentially iterating through known or enumerated notebook identifiers. Third, the application's backend processes the payload, bypasses any conceptual visibility checks, and queries the database or internal state for the requested notebook metadata. Finally, the server serializes the sensitive information—such as internal notebook names, document counts, sizes, and timestamps—into an HTTP response payload and returns it to the unauthenticated client.\nThe network exposure of this vulnerability is significant if the SiYuan instance is deployed without a reverse proxy enforcing perimeter security, as the HTTP interface is directly accessible. Privilege requirements are entirely absent, meaning any unprivileged network entity can successfully trigger the flawed endpoint. The post-exploitation impact is characterized by unauthorized information disclosure, enabling threat actors to map the internal data landscape, identify high-value private workspaces, and gather intelligence for subsequent exploitation phases."
}