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

Quick assessment

Affected
siyuan-note siyuan
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

SiYuan是SiYuan开源的一个隐私至上的个人知识管理系统。 SiYuan 3.6.2之前版本存在访问控制错误漏洞，该漏洞源于WebSocket服务器接受未经身份验证的连接，且未对攻击者控制的JSON进行类型检查，可能导致远程攻击者发送恶意消息触发运行时崩溃，造成拒绝服务。

CVSS 7.5 · High EPSS 0.57% · P46
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I. Basic Information for CVE-2026-33203

Vulnerability Information
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Vulnerability Title
SiYuan has an Unauthenticated WebSocket DoS via Auth Keepalive Bypass
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
未捕获的异常
Source: CVE Program / CVE List V5
Vulnerability Title
SiYuan 访问控制错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
SiYuan是SiYuan开源的一个隐私至上的个人知识管理系统。 SiYuan 3.6.2之前版本存在访问控制错误漏洞，该漏洞源于WebSocket服务器接受未经身份验证的连接，且未对攻击者控制的JSON进行类型检查，可能导致远程攻击者发送恶意消息触发运行时崩溃，造成拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
siyuan-note siyuan < 3.6.2 -

II. Public POCs for CVE-2026-33203

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III. Intelligence Information for CVE-2026-33203

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Vendor Advisories for CVE-2026-33203 (1)

Same Patch Batch · siyuan-note · 2026-03-20 · 8 CVEs total

CVE-2026-32938 9.9 CRITICAL SiYuan has an Arbitrary File Read in its Desktop Publish Service
CVE-2026-32767 9.8 CRITICAL SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API
CVE-2026-32940 9.3 CRITICAL SiYuan has a SanitizeSVG bypass via data:text/xml in getDynamicIcon (incomplete fix for CV
CVE-2026-33476 7.5 HIGH SiYuan has an Unauthenticated Arbitrary File Read via Path Traversal
CVE-2026-33194 6.8 MEDIUM SiYuan has an Incomplete Fix for IsSensitivePath Denylist Allows File Read from /opt, /usr
CVE-2026-33067 SiYuan has Stored XSS to RCE via Unsanitized Bazaar Package Metadata
CVE-2026-33066 SiYuan has Stored XSS to RCE via Unsanitized Bazaar README Rendering

IV. Related Vulnerabilities

Same product: siyuan
Same vendor: siyuan-note
Same weakness: CWE-248

V. Comments for CVE-2026-33203

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