XSS in Siyuan-Note Siyuan
CVE-2026-100643
SiYuan versions before v3.8.4 fail to properly escape four stored Attribute View values in textarea elements, allowing authenticated attackers to inject JavaScript by modifying field descriptions, template sources, select option descriptions, or footer calculation templates. Attackers can execute stored JavaScript when other users open affected database menus, and in the Electron desktop app with nodeIntegration enabled, this leads to command execution with SiYuan process privileges.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.0 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-h3p6-c22r-fx2j (vendor-advisory)
- www.vulncheck.com/advisories/siyuan-before-3.8.4-stored-xss-via-attribute-view-… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100643?
- CVE-2026-100643 is a high-severity vulnerability in Siyuan-Note Siyuan, classified under Cross-site Scripting. CVSS score: 8.0/10. Published 2026-09-26.
- How severe is CVE-2026-100643?
- High severity. CVSS v3 base score is 8.0 out of 10.