CVE-2026-73609 in SiYuan
Summary
by MITRE • 08/13/2026
SiYuan versions before v3.7.4 contain an information disclosure vulnerability in the getBookmarkLabels endpoint that returns all bookmark labels in the workspace without publish-access filtering. Anonymous readers and publish-mode readers can obtain the complete bookmark vocabulary across the workspace, disclosing subject matter and organizational information from inaccessible documents.
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Analysis
by VulDB Data Team • 08/13/2026
This vulnerability exists within the SiYuan note-taking application where version v3.7.4 and earlier contain a critical information disclosure flaw in the getBookmarkLabels endpoint. The technical implementation fails to enforce proper access controls during the retrieval of bookmark labels, allowing unauthorized users to bypass normal permission boundaries that should restrict access to sensitive organizational data. The vulnerability specifically affects the workspace-level bookmark vocabulary retrieval functionality where all bookmark labels are returned regardless of the user's access level or publishing mode status.
The operational impact of this information disclosure vulnerability is significant as it enables anonymous readers and publish-mode readers to obtain complete bookmark vocabularies across entire workspaces. This exposure allows attackers to discover subject matter classifications, organizational structures, and document hierarchies that should remain restricted to authorized personnel only. The disclosure extends beyond simple metadata to reveal comprehensive semantic mappings that could aid in further exploitation attempts or provide insights into internal organizational processes and sensitive information architectures.
From a cybersecurity perspective, this vulnerability aligns with CWE-200 (Information Exposure) and represents a clear violation of the principle of least privilege as defined in cybersecurity frameworks. The flaw demonstrates inadequate input validation and access control mechanisms within the application's API endpoint design, creating an unauthorized data exposure scenario that could facilitate reconnaissance activities for attackers seeking to understand target environments. The vulnerability also intersects with ATT&CK technique T1213.002 (Data from Information Repositories) as it enables unauthorized extraction of organizational knowledge structures.
Mitigation strategies should include implementing proper access control enforcement within the getBookmarkLabels endpoint to ensure that only users with appropriate read permissions can retrieve bookmark labels from specific documents or workspaces. The application should enforce publish-access filtering at the API level to prevent unauthorized exposure of workspace-level bookmark vocabularies. Additionally, all users should be required to authenticate before accessing any bookmark-related functionality, and the system should implement role-based access controls that properly distinguish between anonymous, read-only, and full-access user privileges. The recommended solution involves patching the affected versions to v3.7.4 or later where the access control mechanisms have been properly implemented to prevent unauthorized disclosure of organizational information through bookmark label enumeration.
The vulnerability represents a serious security gap that could enable attackers to perform comprehensive reconnaissance of organizational structures and sensitive content without proper authorization. This type of information exposure often serves as a precursor to more sophisticated attacks where adversaries use the discovered knowledge to plan targeted exploitation attempts. Organizations should immediately implement access control updates and conduct security assessments to ensure no other similar endpoints exist within the application that may suffer from comparable authorization bypass vulnerabilities.