Vulnerability · Published Apr 16, 2026 · Assigned by GitHub_M

CVE-2026-40322SiYuan: Mermaid `javascript:` Link Injection Leads to Stored XSS and Electron RCE

Critical 9.1

In plain English

A critical-severity cross-site scripting in siyuan from siyuan-note. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).

Severity (CVSS 3.1)9.1Critical

Exploit odds (30 days)0.3%top 76.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
siyuan-note	siyuan	< 3.6.4

Weakness: CWE-79, CWE-94 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-x63q-3rcj-hhp5 x_refsource_CONFIRM
https://github.com/siyuan-note/siyuan/releases/tag/v3.6.4 x_refsource_MISC