Auth bypass in B3log Siyuan
CVE-2026-32815
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.
Vulnerability class: Broken Authentication
EPSS: 0.004 (28.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
Affected products
- B3log Siyuan
- Siyuan-note Siyuan — versions < 3.6.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Mitigation, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-32815?
- CVE-2026-32815 is a high-severity vulnerability in B3log Siyuan, classified under Improper Authentication. CVSS score: 7.5/10. Published 2026-03-19.
- How severe is CVE-2026-32815?
- High severity. CVSS v3 base score is 7.5 out of 10.