CVE-2026-33203
WebSocket Unauthenticated Access and DoS in SiYuan Kernel
Publication date: 2026-03-20
Last updated on: 2026-03-23
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| b3log | siyuan | to 3.6.2 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-306 | The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. |
| CWE-248 | An exception is thrown from a function, but it is not caught. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in the SiYuan personal knowledge management system prior to version 3.6.2. The kernel WebSocket server accepts unauthenticated connections if a specific "auth keepalive" query parameter is present. Once connected, the server parses incoming messages using unchecked type assertions on attacker-controlled JSON data. A remote attacker can exploit this by sending malformed messages that cause a runtime panic, potentially crashing the kernel process.
How can this vulnerability impact me? :
The primary impact of this vulnerability is a denial of service condition. An attacker can remotely crash the SiYuan kernel process by sending specially crafted malformed messages, causing the system to become unavailable or unstable.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should upgrade SiYuan to version 3.6.2 or later, as this version fixes the issue where the kernel WebSocket server accepts unauthenticated connections and prevents denial of service caused by malformed messages.