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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.005 (42.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.002
Affected products
- B3log Siyuan
- Siyuan-Note Siyuan — versions < 3.6.1
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-xp2m-98x8-rpj6 (Exploit, Mitigation, Vendor Advisory)
- github.com/siyuan-note/siyuan/commit/1e370e37359778c0932673e825182ff555b504a3 (Patch)
- github.com/siyuan-note/siyuan/releases/tag/v3.6.1 (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.