SiYuan is an open-source personal knowledge management system. In versions 3.6.3 and below, Mermaid diagrams are rendered with securityLevel set to "loose", and the resulting SVG is injected into the DOM via innerHTML. This allows attacker-controlled javascript: URLs in Mermaid code blocks to survive into the rendered output. On desktop builds using Electron, windows are created with nodeIntegration enabled and contextIsolation disabled, escalating the stored XSS to arbitrary code execution when a victim opens a note containing a malicious Mermaid block and clicks the rendered diagram node. This issue has been fixed in version 3.6.4.
History

Fri, 17 Apr 2026 13:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 17 Apr 2026 08:15:00 +0000

Type Values Removed Values Added
First Time appeared Siyuan
Siyuan siyuan
Vendors & Products Siyuan
Siyuan siyuan

Thu, 16 Apr 2026 23:15:00 +0000

Type Values Removed Values Added
Description SiYuan is an open-source personal knowledge management system. In versions 3.6.3 and below, Mermaid diagrams are rendered with securityLevel set to "loose", and the resulting SVG is injected into the DOM via innerHTML. This allows attacker-controlled javascript: URLs in Mermaid code blocks to survive into the rendered output. On desktop builds using Electron, windows are created with nodeIntegration enabled and contextIsolation disabled, escalating the stored XSS to arbitrary code execution when a victim opens a note containing a malicious Mermaid block and clicks the rendered diagram node. This issue has been fixed in version 3.6.4.
Title SiYuan: Mermaid `javascript:` Link Injection Leads to Stored XSS and Electron RCE
Weaknesses CWE-79
CWE-94
References
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-04-16T23:00:07.719Z

Updated: 2026-04-17T12:26:06.118Z

Reserved: 2026-04-10T21:41:54.505Z

Link: CVE-2026-40322

cve-icon Vulnrichment

Updated: 2026-04-17T12:25:52.098Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-04-16T23:16:33.733

Modified: 2026-04-17T15:38:09.243

Link: CVE-2026-40322

cve-icon Redhat

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