CVE-2026-34449 CRITICAL

CVE-2026-34449: SiYuan: Cross-Origin RCE via Permissive CORS Policy and JavaScript Snippet Injection

Vendor Siyuan-Note
Product siyuan
Weakness CWE-942
Published March 31, 2026
Last update April 1, 2026

CVSS base score

9.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

What the vulnerability does

Description

SiYuan is a personal knowledge management system. Prior to version 3.6.2, a malicious website can achieve Remote Code Execution (RCE) on any desktop running SiYuan by exploiting the permissive CORS policy (Access-Control-Allow-Origin: * + Access-Control-Allow-Private-Network: true) to inject a JavaScript snippet via the API. The injected snippet executes in Electron's Node.js context with full OS access the next time the user opens SiYuan's UI. No user interaction is required beyond visiting the malicious website while SiYuan is running. This issue has been patched in version 3.6.2.

Key dates

Disclosure timeline

March 31, 2026 CVE published
April 1, 2026 Record updated