CVE-2026-32815: b3log siyuan Improper Authentication

Vulnerability summary

CVE-2026-32815 is a high (CVSS 7.5) Improper Authentication vulnerability in b3log siyuan. EPSS estimates a 0.55% chance of exploitation in the next 30 days, higher than 44.8% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 19-03-2026
   PublishedVulnerability first disclosed.
2. 20-03-2026
   Last modifiedVulnerability information updated.

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.

• CWE-287Improper AuthenticationWhen an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.