XSS in Siyuan-Note Siyuan
CVE-2026-82654
SiYuan before v3.8.1 fails to properly escape block name, alias, and memo fields in hint, backlink, and breadcrumb rendering functions. Attackers can set a block's name to contain HTML/script tags that execute when another user views documents referencing or displaying that block.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.9 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L.
EPSS exploit prediction
EPSS: 0.004 (28.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.9% 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: 0.004 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-hf87-qh3j-3p88 (vendor-advisory)
- www.vulncheck.com/advisories/siyuan-before-3.8.1-stored-xss-via-block-name (third-party-advisory)
Frequently asked questions
- What is CVE-2026-82654?
- CVE-2026-82654 is a high-severity vulnerability in Siyuan-Note Siyuan, classified under Cross-site Scripting. CVSS score: 8.9/10. Published 2026-08-30.
- How severe is CVE-2026-82654?
- High severity. CVSS v3 base score is 8.9 out of 10.