CVE-2026-32815: b3log Siyuan

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

SiYuan is a personal knowledge management system. In versions 3.6.0 and below, the WebSocket endpoint (/ws) allows unauthenticated connections when specific URL parameters are provided (?app=siyuan&id=auth&type=auth). This bypass, intended for the login page to keep the kernel alive, allows any external client — including malicious websites via cross-origin WebSocket — to connect and receive all server push events in real-time. These events leak sensitive document metadata including document titles, notebook names, file paths, and all CRUD operations performed by authenticated users. Combined with the absence of Origin header validation, a malicious website can silently connect to a victim's local SiYuan instance and monitor their note-taking activity. This issue has been fixed in version 3.6.1.

Affected products

• b3log Siyuan: before 3.6.1 (fixed in 3.6.1)

Published 2026-03-19. Last modified 2026-06-17.