Description

SiYuan versions before v3.7.4 contain a cross-site scripting vulnerability in the unicode2Emoji function that fails to sanitize codepoint branch output. Attackers can craft document icons with hex-encoded markup that executes in the renderer with Node integration enabled, achieving arbitrary code execution on the host system.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.0",
  "pubDate": "2026-08-15T22:16:55.157Z",
  "pubdate": "2026-08-15T22:16:55.157Z",
  "executiveSummary": "An unauthenticated cross-site scripting vulnerability exists within SiYuan versions prior to v3.7.4. The flaw resides in the unicode2Emoji function, which fails to properly sanitize codepoint branch output during the processing of document icons. Because the application runs within an Electron-based renderer environment with Node.js integration enabled, this cross-site scripting flaw escalates from a traditional browser-based script injection into full arbitrary remote code execution on the underlying host operating system.\nThe vulnerability allows an attacker capable of crafting malicious document icons containing hex-encoded markup to achieve complete compromise of the local system upon rendering. The risk implication is critical, as successful exploitation bypasses standard web context boundaries to execute arbitrary system commands via native Node.js APIs accessible within the privileged DOM context. Remediation requires updating the software to version v3.7.4 or later where the sanitization defect is addressed.",
  "technicalDetails": "The root cause of the vulnerability is insufficient input sanitization and output encoding within the unicode2Emoji function of SiYuan. Specifically, the function processes unicode codepoint branch outputs for document icons without properly neutralizing HTML markup or script contexts. When a user opens or synchronizes a maliciously crafted document containing specially formulated hex-encoded markup within the icon field, the application interprets and renders the payload directly inside the Document Object Model.\nExploitation is facilitated by the architectural configuration of the SiYuan desktop application renderer, which explicitly maintains Node integration enabled. This security context permits scripts executing within the renderer process to access native Node.js modules, including child_process, fs, and os. Consequently, the injected hex-encoded markup executes JavaScript that can instantiate child processes to run arbitrary operating system commands, read or write arbitrary files, and fully compromise the host machine.\nThe attack flow proceeds as follows: First, an attacker crafts a malicious document containing a specially encoded icon string leveraging the vulnerability in unicode2Emoji. Second, the victim imports, opens, or syncs the document within the SiYuan application. Third, the renderer parses the codepoint branch output for the document icon, failing to sanitize the malicious hex-encoded payload. Fourth, the injected script executes within the privileged Electron renderer context with Node integration enabled. Fifth, the payload leverages Node.js APIs to achieve arbitrary code execution on the host system.\nThe vulnerability affects SiYuan versions prior to v3.7.4. Exploitation does not require prior authentication or specialized privileges within the application if the victim processes untrusted documents, and the attack vector is triggered locally or via document synchronization mechanisms."
}