SiYuan versions prior to 3.8.4 contain a path‑traversal flaw in the setNotebookIcon API. The flaw allows an authenticated administrator to escape the workspace data directory and write files to arbitrary locations. Attackers can inject a specially crafted notebook name that contains traversal sequences, causing the server to create directories and files outside the intended folder. By writing a conf.json file in a location that the kernel process can read, an attacker can influence application configuration and potentially execute arbitrary code, resulting in full control of the system.

All Siyuan Note installations built by siyuan-note prior to release 3.8.4 are affected. The flaw applies to the setNotebookIcon endpoint, which can be accessed by any user with administrative privileges. Users running older versions of the software should verify whether their deployment is above 3.8.4; if not, the software is vulnerable.

With a CVSS score of 8.3 the vulnerability is considered high severity. The EPSS score is currently unavailable, and the issue is not listed in the CISA KEV catalog. Exploitation requires the attacker to be authenticated as an administrator, but once authenticated, the path traversal can be exercised over the network via the normal setNotebookIcon request. The resulting ability to write conf.json files that are read by the kernel process makes the outcome potentially catastrophic, equivalent to remote code execution, especially in environments where the kernel accesses configuration files for privileged operations.