Description

SiYuan versions before v3.7.4 fail to enforce publish-access checks on getBlockBreadcrumb, getRefText, and getBlockTreeInfos endpoints, allowing disclosure of protected document content and metadata. Anonymous readers or publish RoleReader accounts can retrieve document titles, ancestor block content snippets, reference text, and path metadata for publish-forbidden or password-protected documents by supplying block IDs.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.8",
  "pubDate": "2026-08-12T20:17:52.527Z",
  "pubdate": "2026-08-12T20:17:52.527Z",
  "executiveSummary": "An authorization bypass vulnerability exists in SiYuan versions prior to v3.7.4, specifically within the API endpoints responsible for metadata and content retrieval.\nThe vulnerability allows unauthorized or under-privileged users, including anonymous readers and accounts assigned the publish RoleReader role, to successfully bypass publish-access enforcement mechanisms.\nThe core impact of this security flaw is the unauthorized disclosure of sensitive document contents, titles, ancestor block content snippets, reference text, and path metadata.\nThis exposure affects documents that are explicitly designated as publish-forbidden or protected by passwords.\nAttackers with basic network access and minimal privileges can exploit this flaw by directly querying specific endpoints with arbitrary block IDs.\nThe risk implication is significant unauthorized information disclosure, compromising data confidentiality for private or restricted notes within affected SiYuan deployments.",
  "technicalDetails": "The root cause of the vulnerability is the absence of adequate publish-access validation checks on specific server endpoints.\nThe vulnerable components comprise the getBlockBreadcrumb, getRefText, and getBlockTreeInfos endpoints.\nAffected software versions include all SiYuan releases prior to v3.7.4.\nAuthentication and privilege requirements for exploitation are minimal; attackers require only anonymous access or low-privilege publish RoleReader status.\nThe vulnerability is exposed over the network where the SiYuan application instance is accessible.\nExploitation occurs due to the failure of the backend application logic to verify whether the requesting user possesses the necessary permissions to access restricted, publish-forbidden, or password-protected resources.\nThe attack flow proceeds as follows: an unauthorized or low-privileged attacker identifies or guesses target block IDs belonging to restricted documents.\nThe attacker then crafts direct HTTP requests targeting the vulnerable endpoints getBlockBreadcrumb, getRefText, or getBlockTreeInfos, supplying the targeted block IDs as parameters.\nUpon receiving the request, the vulnerable endpoints process the input and return the requested metadata, ancestor block content snippets, reference text, and path structures without enforcing the required security policies or password validations.\nPost-exploitation impact includes the systematic harvesting of sensitive structural data, hierarchical paths, and textual contents of protected documents, directly violating the intended access control model."
}