CVE-2026-33203

SiYuan has an Unauthenticated WebSocket DoS via Auth Keepalive Bypass

State: Published
Severity: 7.5 High
Published: Mar 20, 2026
Updated: Mar 23, 2026
Reserved: Mar 17, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	GitHub_M

Weaknesses

CWE-248 Uncaught Exception
CWE-306 Missing Authentication for Critical Function

Affected Products

Product	Versions
siyuansiyuan-note	< 3.6.2Affected

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3g9h-9hp4-654v

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