Description

SiYuan versions before v3.7.4 contain a path traversal vulnerability in the getUniqueFilename endpoint that allows anonymous readers to probe filesystem existence without validation or confinement. Attackers can supply arbitrary absolute paths to determine whether files and directories exist on the host, enabling reconnaissance of the filesystem layout and installed software.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.8",
  "pubDate": "2026-08-13T12:17:24.897Z",
  "pubdate": "2026-08-13T12:17:24.897Z",
  "executiveSummary": "SiYuan versions before v3.7.4 are affected by a path traversal vulnerability residing within the getUniqueFilename endpoint.\nThis security flaw enables anonymous readers to perform unauthorized filesystem existence probing without proper validation or directory confinement.\nThe primary impact of this vulnerability is unauthorized reconnaissance, allowing malicious actors to supply arbitrary absolute paths to determine the presence or absence of specific files and directories on the host operating system.\nBy leveraging this capability, attackers can map out the internal filesystem layout, identify installed software, and gather critical intelligence to facilitate subsequent, more targeted attacks.\nThe risk implication is elevated due to the lack of authentication requirements for the vulnerable endpoint, permitting unauthenticated external entities to interact with backend routing logic designed for file management operations.\nNo complex exploitation requirements are specified other than network accessibility to the vulnerable SiYuan instance and the ability to issue HTTP requests to the target endpoint.",
  "technicalDetails": "The root cause of the vulnerability stems from insufficient input sanitization, validation, and path confinement checks within the getUniqueFilename endpoint of SiYuan.\nThe vulnerable component fails to properly restrict user-supplied input to a designated safe base directory, allowing absolute paths to be processed by the underlying file handling routines.\nAffected versions include all SiYuan deployments prior to v3.7.4.\nThe authentication requirement for this endpoint is absent, allowing anonymous readers to access the functionality without credentials.\nNo special privilege requirements are necessary to trigger the flaw, and the network exposure corresponds to the accessibility of the SiYuan web interface or API.\nThe attack flow proceeds as follows: An unauthenticated attacker crafts an HTTP request targeting the getUniqueFilename endpoint.\nInstead of providing a relative filename within the expected workspace or application directory, the attacker supplies an arbitrary absolute path pointing to a target file or directory on the host filesystem.\nThe application processes the input through the vulnerable function without verifying whether the resulting path escapes the intended root directory.\nDepending on how the application handles the existence check and returns its response, the attacker analyzes the output or error behavior to infer whether the targeted file or directory exists on the host.\nThis payload behavior enables systematic filesystem reconnaissance, exposing structural details of the host operating system and aiding in the discovery of sensitive files, configurations, or installed software packages."
}