Description

SiYuan versions before 3.8.4 fail to escape bookmark labels imported from notebook files when rendering them in the dock tree. Attackers can craft malicious .sy notebook files with unescaped HTML in bookmark attributes that execute scripts in the Electron renderer with access to child_process for command execution.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-17T15:17:01.840Z",
  "pubdate": "2026-09-17T15:17:01.840Z",
  "executiveSummary": "SiYuan versions prior to 3.8.4 are susceptible to a Cross-Site Scripting (XSS) vulnerability stemming from improper input sanitization of bookmark labels within imported notebook files.\nThe vulnerability allows an attacker to inject malicious HTML/JavaScript into the application's dock tree rendering process.\nDue to the underlying Electron framework architecture, successfully executed scripts gain access to the Node.js integration, specifically the 'child_process' module.\nThis creates a critical Remote Code Execution (RCE) vector, enabling the attacker to execute arbitrary system commands with the privileges of the SiYuan application process.\nExploitation requires a user to import a maliciously crafted .sy notebook file, making this a client-side execution vulnerability that circumvents standard security boundaries.\nThe risk is severe as it permits full system compromise, data exfiltration, or the installation of persistent malicious payloads on the host machine.",
  "technicalDetails": "The vulnerability exists within the rendering logic of the SiYuan dock tree component, which fails to adequately sanitize or escape bookmark label attributes extracted from imported .sy notebook files.\nWhen a user imports a specially crafted notebook file, the application parses the file structure and reflects bookmark metadata into the Document Object Model (DOM) of the Electron-based renderer process.\nThe root cause is a lack of output encoding/sanitization during the dynamic generation of UI elements, allowing for the injection of arbitrary HTML tags, including <script> elements and event handlers (e.g., onload, onerror).\nBecause the application is built using Electron, the renderer process environment frequently maintains Node.js integration, granting access to privileged modules such as 'child_process'.\nThe attack flow begins with the creation of a .sy notebook file where the bookmark label field contains an obfuscated JavaScript payload designed to leverage Node.js APIs.\nUpon importing the file, the SiYuan application renders the malicious label; the JavaScript payload executes within the context of the renderer process.\nThe attacker utilizes the context to invoke 'require('child_process').execSync()' or similar methods to spawn shell commands, providing a direct bridge from a browser-based XSS vulnerability to OS-level code execution.\nThis vulnerability does not require authentication or network exposure to trigger, as the malicious payload is embedded directly into the application data file, which the target user must manually or automatically import.\nThe scope of the impact is limited only by the permissions of the user account running the SiYuan application, allowing for potential lateral movement, persistence via startup scripts, or exfiltration of the local user's data vault."
}