Auth bypass in Siyuan-Note Siyuan
CVE-2026-72803
SiYuan versions before v3.7.4 fail to enforce publish-access checks in the getBlockAttrs and batchGetBlockAttrs endpoints. Attackers can retrieve block attributes including names, aliases, memos, and custom fields from protected documents by sending POST requests with block IDs.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (23.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · 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-qvq9-hq6p-v378 (vendor-advisory)
- www.vulncheck.com/advisories/siyuan-before-information-disclosure-via-getblocka… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-72803?
- CVE-2026-72803 is a medium-severity vulnerability in Siyuan-Note Siyuan, classified under Missing Authorization. CVSS score: 5.8/10. Published 2026-08-12.
- How severe is CVE-2026-72803?
- Medium severity. CVSS v3 base score is 5.8 out of 10.