Description

SiYuan before v3.7.4 contains an information disclosure vulnerability in the /api/filetree/authFilePublishAccess endpoint, which is registered with CheckAuth only and is reachable anonymously. The endpoint never sets a failure code, so its outcome is signalled entirely by the response message and by the presence of a Set-Cookie header, and these signals differ across access tiers. By submitting requests with an empty password for a candidate document identifier, an anonymous attacker can distinguish whether a document is public/nonexistent, password-protected, or exists at the hidden or forbidden tier, thereby confirming the existence of documents they are not permitted to access. Because hidden and forbidden entries store an empty password, such requests also cause the server to issue a publish-auth cookie for forbidden documents.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.8",
  "pubDate": "2026-08-14T12:16:47.940Z",
  "pubdate": "2026-08-14T12:16:47.940Z",
  "executiveSummary": "SiYuan before v3.7.4 suffers from an information disclosure vulnerability residing within the /api/filetree/authFilePublishAccess endpoint. This security flaw allows unauthenticated remote attackers to determine the existence and accessibility status of arbitrary documents by leveraging differential response behavior, including message variations and the issuance of Set-Cookie headers.\nThe vulnerability exposes sensitive data categorization regarding public, nonexistent, password-protected, hidden, and forbidden document tiers. An unauthenticated attacker can exploit this flaw by submitting HTTP requests containing an empty password parameter for candidate document identifiers.\nDue to improper handling of hidden and forbidden document tiers where an empty password is conventionally stored, successful exploitation causes the server to inadvertently issue a publish-auth cookie for unauthorized forbidden documents. This results in broken access controls, unauthorized resource enumeration, and the bypassing of authorization checks for restricted content.\nThe risk implications include privacy violations, unauthorized document enumeration, and potential unauthorized access to protected or hidden repository data without requiring prior credentials or elevated privileges.",
  "technicalDetails": "The vulnerability stems from flawed endpoint implementation and access control validation within the /api/filetree/authFilePublishAccess component of SiYuan before v3.7.4. Although the endpoint is registered with CheckAuth, it permits anonymous reachability due to improper session or authentication enforcement.\nThe vulnerable component fails to enforce strict failure status codes, signaling outcomes entirely through specific response messages and the presence of a Set-Cookie header. These differential signals allow an observer to accurately map the state of target documents across various access tiers.\nThe attack flow proceeds as follows: An unauthenticated attacker targets the network-exposed /api/filetree/authFilePublishAccess endpoint. The attacker crafts iterative HTTP requests substituting candidate document identifiers and supplying an empty password parameter.\nUpon receiving the request, the application processes the document identifier and compares the access tiers. Because hidden and forbidden entries natively store an empty password, the server evaluates the empty password submission as valid for these restricted tiers.\nConsequently, the server issues a publish-auth cookie for forbidden documents that the attacker is strictly not permitted to access. By analyzing the differential response messages and observing the returned Set-Cookie headers, the attacker confirms the existence of documents and differentiates between public, nonexistent, password-protected, hidden, and forbidden tiers.\nThe technical prerequisites for this attack involve network connectivity to the SiYuan instance exposing the API endpoint. No authentication credentials or low-privilege sessions are required, as the endpoint is accessible anonymously, enabling automated enumeration and post-exploitation state confusion."
}