CVE-2026-66395: Siyuan-Note Siyuan

Critical severity, CVSS 9.6. EPSS: 0.6% chance of exploitation in the next 30 days.

SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin readme handler that allows attackers to execute arbitrary code by crafting a malicious siyuan:// deep link. Attackers can inject HTML payloads via the plugin name parameter that execute with full Node.js access through insertAdjacentHTML rendering in an insecurely configured Electron renderer.

Affected products

• Siyuan-Note Siyuan: before 3.7.2 (fixed in 3.7.2)

Published 2026-07-27. Last modified 2026-09-17.