CVE-2026-40322: SiYuan: Mermaid `javascript:` Link Injection Leads to Stored XSS and Electron RCE
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 Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-40322?
The severity of CVE-2026-40322 is classified as high due to its potential for stored XSS and remote code execution.
How do I fix CVE-2026-40322?
To fix CVE-2026-40322, upgrade SiYuan to version 3.6.4 or later, where the securityLevel is set to 'strict'.
What types of attacks does CVE-2026-40322 allow?
CVE-2026-40322 allows for stored cross-site scripting (XSS) attacks and remote code execution within Electron applications.
Which versions of SiYuan are affected by CVE-2026-40322?
SiYuan versions 3.6.3 and below are affected by CVE-2026-40322.
Where can I find more information about CVE-2026-40322?
More information about CVE-2026-40322 can be found in the security advisories section of the SiYuan GitHub repository.