CVE-2026-32815: SiYuan: Cross-Origin WebSocket Hijacking via Authentication Bypass — Unauthenticated Information Disclosure

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-03-19 · updated 2026-06-17
Weakness: CWE-287

Description

SiYuan is a personal knowledge management system. In versions 3.6.0 and below, the WebSocket endpoint (/ws) allows unauthenticated connections when specific URL parameters are provided (?app=siyuan&id=auth&type=auth). This bypass, intended for the login page to keep the kernel alive, allows any external client — including malicious websites via cross-origin WebSocket — to connect and receive all server push events in real-time. These events leak sensitive document metadata including document titles, notebook names, file paths, and all CRUD operations performed by authenticated users. Combined with the absence of Origin header validation, a malicious website can silently connect to a victim's local SiYuan instance and monitor their note-taking activity. This issue has been fixed in version 3.6.1.

Affected products

siyuan-note siyuan: before 3.6.1 — fixed in 3.6.1

How to fix

Upgrade to a fixed version: siyuan-note siyuan 3.6.1. Check the vendor advisory for mitigations.

References

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