XSS in Siyuan-Note Siyuan
CVE-2026-93923
SiYuan through 3.8.4 fails to escape heading style attributes when rendering outline and bookmark dock HTML, allowing stored cross-site scripting. Attackers can supply crafted notebooks or call administrative endpoints to inject malicious style values that execute in the Electron renderer with full system access.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (48.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-928g-4hfq-qwvx (vendor-advisory)
- github.com/siyuan-note/siyuan (product)
- github.com/siyuan-note/siyuan/blob/v3.8.4/kernel/model/render.go (technical-description)
- github.com/siyuan-note/siyuan/blob/v3.8.4/app/src/util/Tree.ts (technical-description)
- github.com/siyuan-note/siyuan/blob/v3.8.4/app/src/util/Tree.ts (technical-description)
- www.vulncheck.com/advisories/siyuan-through-3.8.4-stored-xss-via-heading-style-… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-93923?
- CVE-2026-93923 is a high-severity vulnerability in Siyuan-Note Siyuan, classified under Cross-site Scripting. CVSS score: 8.8/10. Published 2026-09-19.
- How severe is CVE-2026-93923?
- High severity. CVSS v3 base score is 8.8 out of 10.