Executive brief
SiYuan is an open-source personal knowledge management application. A vulnerability in versions before 3.8.4 allows attackers to execute arbitrary code by injecting malicious HTML/JavaScript into document titles, which are rendered without proper escaping in the backlink panel. This gives attackers access to dangerous system functions like command execution.
Technical details
The vulnerability is a cross-site scripting (XSS) flaw in the backlink dock tree component, where document titles are rendered as unescaped HTML markup. An attacker can craft malicious titles via the rename API or through specially crafted notebook files to inject JavaScript that executes in the Electron renderer context. Because SiYuan runs as an Electron application, the JavaScript context has access to child_process and other Node.js APIs, allowing arbitrary command execution on the host system. No authentication or special privileges are required; a user need only open a notebook containing a document with a malicious title. Patches are available in version 3.8.4 and later.
Affected products
- SiYuan SiYuan before 3.8.4
Timeline
- 2026-09-17: disclosed
- 2026-09-17: patched: Version 3.8.4 and later