Vulnerability 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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| B3Log | Siyuan | < 3.6.4 |
Related Weaknesses (CWE)
References
- https://github.com/siyuan-note/siyuan/releases/tag/v3.6.4Release Notes
- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-x63q-3rcj-hhp5Third Party Advisory
- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-x63q-3rcj-hhp5Third Party Advisory
FAQ
What is CVE-2026-40322?
CVE-2026-40322 is a vulnerability with a CVSS score of 9.0 (CRITICAL). 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 ...
How severe is CVE-2026-40322?
CVE-2026-40322 has been rated CRITICAL with a CVSS base score of 9.0/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-40322?
Check the references section above for vendor advisories and patch information. Affected products include: B3Log Siyuan.