CVE-2026-59855 in SiYuan
Summary
by MITRE • 07/10/2026
SiYuan is an open-source personal knowledge management system. Prior to 3.7.1, Asset.render in app/src/asset/index.ts interpolates the unsanitized this.path value into HTML assigned to innerHTML, allowing a crafted asset link containing a double quote to break out of the src attribute, inject an event handler, and execute JavaScript that can run OS commands in the Electron renderer. This issue is fixed in versions 3.7.1-alpha.2 and 3.7.1.
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Analysis
by VulDB Data Team • 07/10/2026
The vulnerability exists within SiYuan's asset handling functionality where the Asset.render method in app/src/asset/index.ts fails to properly sanitize user-supplied path values before incorporating them into HTML content. This represents a classic cross-site scripting vulnerability that leverages improper input validation and output encoding practices. The flaw occurs when the system assigns the unsanitized this.path value directly into HTML through innerHTML assignment, creating an opportunity for malicious actors to inject arbitrary JavaScript code.
The technical exploitation mechanism relies on the ability to manipulate the asset link structure to break out of the expected HTML attribute context. Specifically, a crafted asset link containing a double quote character can escape the src attribute boundaries and inject event handlers such as onclick or onload attributes. This injection capability allows attackers to execute arbitrary JavaScript within the Electron renderer process, which operates with elevated privileges compared to standard web browsers. The vulnerability's severity is amplified by the fact that the injected JavaScript can leverage Electron's nodeIntegration capabilities to execute operating system commands directly from the renderer process.
This vulnerability falls under CWE-79 - Improper Neutralization of Input During Web Page Generation and specifically relates to CWE-116 - Improper Encoding or Escaping of Output. The attack vector aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: JavaScript, as the exploitation involves executing JavaScript code in the renderer context. The impact extends beyond typical web application attacks because Electron applications often have access to system resources through node.js integration, making this a particularly dangerous vulnerability for desktop applications.
The operational consequences of this vulnerability are severe as it allows for complete compromise of the affected system when an attacker can convince a user to interact with a maliciously crafted asset link. The attack requires user interaction but can lead to full system compromise since the renderer process typically has access to file system operations and can execute arbitrary commands through node.js integration. The remediation strategy involves implementing proper input sanitization and output encoding mechanisms before incorporating user-supplied data into HTML content, specifically ensuring that path values are properly escaped for HTML contexts.
Security best practices dictate that all user-provided input should be treated as untrusted and properly sanitized before being used in any context where it might be interpreted as code. The fix implemented in versions 3.7.1-alpha.2 and 3.7.1 demonstrates the importance of proper HTML escaping and input validation, particularly in applications that combine web technologies with native system capabilities through frameworks like Electron. Organizations using SiYuan should immediately update to these fixed versions and implement additional monitoring for suspicious asset link usage patterns. The vulnerability highlights the critical need for security testing of desktop applications built with modern web technologies, as the interaction between browser-based rendering and native system access creates unique attack surfaces not typically present in traditional web applications.
The remediation process requires comprehensive input validation that ensures all user-supplied path values are properly escaped before HTML insertion, implementing proper context-aware escaping mechanisms, and potentially adopting more secure alternative approaches such as template literals or DOM manipulation methods that do not rely on innerHTML assignment with unsanitized data. Additionally, the application should implement strict content security policies to limit the execution of inline scripts and restrict access to potentially dangerous APIs within the renderer process.