CVE-2026-100645 in SiYuan
Summary
by MITRE • 09/26/2026
SiYuan versions 3.7.0 before 3.8.4 contain a stored cross-site scripting vulnerability in gallery and kanban database renderers where field descriptions are not escaped in aria-label attributes. In the Electron desktop app with nodeIntegration enabled, attackers can inject JavaScript that calls Node.js child_process APIs to execute arbitrary commands with user privileges.
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Analysis
by VulDB Data Team • 09/26/2026
The security flaw identified in SiYuan versions prior to 3.8.4 represents a critical intersection of web application vulnerabilities and desktop environment misconfigurations. The core issue is classified as a stored cross-site scripting vulnerability, which falls under the Common Weakness Enumeration category CWE-79 for Improper Neutralization of Input During Web Page Generation. In this specific context, the flaw resides within the gallery and kanban database renderers used by the application. When users input field descriptions into these components, the system fails to properly sanitize or escape special characters before embedding them into aria-label attributes in the generated HTML structure. This lack of proper output encoding allows malicious scripts to be persisted on the server side or within local storage, ensuring that any user viewing the affected content will trigger the execution of the injected code upon rendering.
The severity of this vulnerability is significantly amplified by the architectural design choices made for the SiYuan Electron desktop application. Unlike standard web browsers which enforce strict same-origin policies and sandboxing to prevent script access to system resources, the specific configuration in question enables nodeIntegration within the renderer process. This setting allows JavaScript running inside the browser window to directly interact with Node.js APIs. Consequently, an attacker who successfully injects a malicious payload via the unescaped aria-label attribute can bypass typical web security boundaries. The injected script is not merely capable of stealing cookies or session tokens as in traditional XSS attacks; it gains access to powerful system-level interfaces provided by the underlying runtime environment.
The operational impact of this vulnerability extends far beyond data theft or defacement, reaching into full remote code execution capabilities. Because nodeIntegration is enabled, the malicious JavaScript can invoke Node.js child_process APIs. These APIs allow for the spawning of new processes on the host operating system with the same privileges as the user running the SiYuan application. This means an attacker does not need to exploit a separate privilege escalation flaw; they can directly execute arbitrary commands such as downloading malware, exfiltrating sensitive files from local directories, or modifying system configurations. The attack vector is particularly insidious because it relies on social engineering or compromised content injection rather than exploiting network-facing services, making detection by perimeter security controls difficult.
From a threat intelligence perspective, this vulnerability aligns with the MITRE ATT&CK technique T1059 Command and Scripting Interpreter, specifically regarding JavaScript execution within desktop applications. It also reflects risks associated with improper sandbox configuration in Electron-based apps, where developers inadvertently expose Node.js capabilities to untrusted web content. The persistence of the payload via stored XSS ensures that the threat remains active until the vulnerable field is modified or deleted by an administrator or user, creating a long-term risk for organizations relying on SiYuan for collaborative knowledge management.
Mitigation strategies must address both the immediate code flaw and the broader architectural security posture. For users currently running affected versions, upgrading to version 3.8.4 or later is the primary remediation step as it resolves the input validation issue within the gallery and kanban renderers. However, a more robust long-term solution involves re-evaluating the use of nodeIntegration in Electron applications. Security best practices dictate that renderer processes should operate with nodeIntegration disabled to prevent direct access to Node.js APIs. If inter-process communication is required for legitimate functionality, developers should utilize context isolation and preload scripts with carefully scoped IPC channels rather than exposing full system capabilities. Additionally, implementing strict Content Security Policy headers can provide an additional layer of defense by restricting the sources from which executable scripts are loaded, thereby mitigating the impact even if input validation fails in future updates.