Auth bypass in Siyuan-Note Siyuan
CVE-2026-72812
SiYuan versions before v3.7.4 contain a missing authorization vulnerability in the /api/ref/refreshBacklink endpoint that allows anonymous readers to trigger persistent server-side writes. Attackers can invoke the endpoint with an attacker-controlled block ID to flush transaction queues, scan all references globally, and enqueue database writes, bypassing read-only protections and enabling resource amplification attacks.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L.
EPSS exploit prediction
EPSS: 0.004 (29.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 29.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Siyuan-Note Siyuan — versions 0, 3.7.4
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-wgwx-479j-23vq (vendor-advisory)
- www.vulncheck.com/advisories/siyuan-before-missing-authorization-via-refreshbac… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-72812?
- CVE-2026-72812 is a medium-severity vulnerability in Siyuan-Note Siyuan, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-08-14.
- How severe is CVE-2026-72812?
- Medium severity. CVSS v3 base score is 6.5 out of 10.