SiYuan is a personal knowledge management system. Prior to version 3.1.16, an arbitrary file read vulnerability exists in Siyuan's `/api/template/render` endpoint. The absence of proper validation on the path parameter allows attackers to access sensitive files on the host system. Version 3.1.16 contains a patch for the issue.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.