CVE-2026-33203 HIGH

CVE-2026-33203: SiYuan has an Unauthenticated WebSocket DoS via Auth Keepalive Bypass

Vendor Siyuan-Note
Product siyuan
Weakness CWE-248
Published March 20, 2026
Last update March 23, 2026

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 20, 2026 CVE published
March 23, 2026 Record updated