CVE-2026-40322: 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"…

PriorityP349critical9CVSS 3.1

AVNACLPRLUIRSCCHIHAH

EPSS

0.31%

22.2th percentile

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.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
b3log	siyuan	< 3.6.4	3.6.4
siyuan-note	siyuan	< 3.6.4	3.6.4

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