CVE-2026-40322

CRITICAL

9.0

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.

CVE Details

CVSS v3.1 Score9.0

SeverityCRITICAL

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredLOW

User InteractionREQUIRED

Published4/16/2026

Last Modified4/20/2026

Sourcenvd

Honeypot Sightings0

Affected Products

b3log:siyuan

Weaknesses (CWE)

CWE-79CWE-94

References

https://github.com/siyuan-note/siyuan/releases/tag/v3.6.4(security-advisories@github.com)

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-x63q-3rcj-hhp5(security-advisories@github.com)

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-x63q-3rcj-hhp5(134c704f-9b21-4f2e-91b3-4a467353bcc0)

IOC Correlations

No correlations recorded

This product uses data from the NVD API but is not endorsed or certified by the NVD.