CVE-2026-34449CWE-942

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

Critical · published March 31, 2026

CVSS v3.1
9.7
EPSS
1%
Percentile
56.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.7 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00803 · 56.3th percentile
Weakness
CWE-942 · Permissive Cross-domain Security Policy with Untrusted Domains
Published
2026-03-31T21:45Z
EPSS history
Timeline
  • 31 MAR 21:45Z
    SiYuan: Cross-Origin RCE via Permissive CORS Policy and JavaScript Snippet Injection
    cvelistv5