TI-2026-25624 Aliases CVE-2026-33203 GHSA-3g9h-9hp4-654v

SiYuan has an Unauthenticated WebSocket DoS via Auth Keepalive Bypass

HIGH 72CWE-248Published 2026-03-20 · Updated 2026-03-23

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service, Security bypass
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-248 and CWE-306.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00528 44th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed siyuan (siyuan-note): 3.6.2github.com/siyuan-note/siyuan/kernel (Go): 3.6.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
siyuan-note	siyuan	before 3.6.2	3.6.2	Patch available	CNA
—	github.com/siyuan-note/siyuan/kernel (Go)	before 3.6.2	3.6.2	Patch available	GHSA-3g9h-9hp4-654v

siyuan Vendorsiyuan-note Affected before 3.6.2 Fixed in 3.6.2 Patch available CNA
github.com/siyuan-note/siyuan/kernel (Go) Vendor— Affected before 3.6.2 Fixed in 3.6.2 Patch available GHSA-3g9h-9hp4-654v

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:b3log:siyuan::::::::	before 3.6.2	Vulnerable	siyuan-note

cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:* Versions before 3.6.2 Vulnerable ·siyuan-note

Remediation

Fix · CNA siyuan (siyuan-note) Fixed in 3.6.2
Fix · GHSA-3g9h-9hp4-654v github.com/siyuan-note/siyuan/kernel (Go) Fixed in 3.6.2 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-33203
2026-10-03 Alias added: GHSA-3g9h-9hp4-654v
2026-11-05 1 new reference · GHSA-3g9h-9hp4-654v

References

Exploit 1

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

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-33203

Other 2

TI-2026-26050 SiYuan has directory traversal within its publishing service CVSS 3.1CRITICAL 9.8
TI-2026-25256 SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API CVSS 3.1CRITICAL 9.8
TI-2024-35827 A SQL injection vulnerability was discovered in Siyuan 3.1.11 in /getHistoryItems. CVSS 3.1CRITICAL 9.8
TI-2024-35826 A SQL injection vulnerability has been identified in Siyuan 3.1.11 via the ids array parameter in /batchGetBlockAttrs. CVSS 3.1CRITICAL 9.8
TI-2024-35825 A SQL injection vulnerability has been identified in Siyuan 3.1.11 via the id parameter at /getAssetContent. CVSS 3.1CRITICAL 9.8
TI-2024-35824 A SQL injection vulnerability has been identified in Siyuan 3.1.11 via the notebook parameter in /searchHistory. CVSS 3.1CRITICAL 9.8

See all 54 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences