CVE-2026-34449

CRITICAL

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

Title source: cna
STIX 2.1

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.

Scores

CVSS v3 9.6
EPSS 0.0014
EPSS Percentile 33.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact total

Details

CWE
CWE-942
Status published
Products (3)
b3log/siyuan < 3.6.2
siyuan-note/siyuan 0 - 3.6.2Go
siyuan-note/siyuan < 3.6.2
Published Mar 31, 2026
Tracked Since Apr 01, 2026