Description

SiYuan before 3.8.2 trusts the attacker-writable text/siyuan clipboard MIME type and skips sanitization in the paste handler, allowing code execution in the Node-enabled desktop renderer. Attackers can craft malicious web pages that write to the clipboard, and when pasted into SiYuan, injected scripts execute with full Node.js access through the Electron main process.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-08T12:16:59.990Z",
  "pubdate": "2026-09-08T12:16:59.990Z",
  "executiveSummary": "SiYuan versions prior to 3.8.2 contain a critical vulnerability involving the insecure handling of clipboard data. The application fails to sanitize content transferred via the 'text/siyuan' MIME type, allowing an attacker to inject malicious payloads into the paste buffer.\nThis vulnerability is classified as an Arbitrary Code Execution (ACE) flaw. Because SiYuan utilizes an Electron-based architecture with Node.js integration enabled in the renderer process, successful exploitation allows the execution of arbitrary JavaScript code with full access to the underlying operating system.\nThe attack is triggered when a user copies content from a malicious web page and subsequently pastes it into the SiYuan desktop application. This requires no specific user authentication within the application itself, as the exploit relies on the trusted relationship between the clipboard and the internal paste handler.\nThe risk implication is severe, as the compromised renderer process can leverage Node.js APIs to perform unauthorized file system operations, execute shell commands, or establish persistent backdoors, effectively bypassing typical web-based sandbox protections.",
  "technicalDetails": "The root cause of this vulnerability lies in the insufficient validation and sanitization of incoming clipboard data handled by the SiYuan desktop application. Specifically, the application explicitly trusts the 'text/siyuan' MIME type, which is intended for internal data exchange but is mutable by external processes, such as a browser environment.\nThe attack flow commences when an adversary lures a target user to a malicious web page. Using the Clipboard API, the attacker writes a crafted payload formatted as 'text/siyuan' to the system clipboard. When the user interacts with the SiYuan application and performs a paste operation, the application's internal paste handler retrieves the malicious content without applying necessary sanitization routines.\nBecause the SiYuan desktop renderer is configured with Node.js integration enabled (nodeIntegration: true), the execution context is not restricted by typical browser-side sandboxing. When the malformed 'text/siyuan' content is processed and parsed by the application's renderer, any embedded scripts are executed with the privileges of the main Electron process.\nThis allows the attacker to move from script execution to full system compromise. Using Node.js primitives like 'require('child_process')' or 'fs', an attacker can read sensitive user files, modify application configurations, or spawn reverse shells. This exploit bypasses the security boundaries typically enforced by Electron by abusing the trust relationship between the application's input processing logic and the operating system clipboard buffer.\nThis vulnerability affects all SiYuan desktop versions prior to 3.8.2. Exploitation is 'client-side' in nature, requiring no network-level authentication, as the execution is triggered locally by the interaction between the clipboard and the vulnerable renderer component. The primary constraint for the attacker is the need for the user to visit a malicious source that triggers the clipboard write event."
}