CVE-2026-33203: b3log Siyuan

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

SiYuan is a personal knowledge management system. Prior to version 3.6.2, the SiYuan kernel WebSocket server accepts unauthenticated connections when a specific "auth keepalive" query parameter is present. After connection, incoming messages are parsed using unchecked type assertions on attacker-controlled JSON. A remote attacker can send malformed messages that trigger a runtime panic, potentially crashing the kernel process and causing denial of service. Version 3.6.2 fixes the issue.

Affected products

• b3log Siyuan: before 3.6.2 (fixed in 3.6.2)

Published 2026-03-20. Last modified 2026-06-17.