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CVE-2026-33203

HIGH CVSS 3.1: 7.5 EPSS 0.05%
Updated Mar 23, 2026
Siyuan-Note
Parameter Value
CVSS 7.5 (HIGH)
Affected Versions before 3.6.2
Fixed In 3.6.2
Type CWE-306 (Missing Authentication for Critical Function), CWE-248 (Uncaught Exception)
Vendor Siyuan-Note
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Vulnerable Products 1

Configuration From (including) Up to (excluding)
B3log Siyuan
cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*
3.6.2