XSS in B3log Siyuan
CVE-2026-23847
SiYuan is a personal knowledge management system. Versions prior to 3.5.4 are vulnerable to reflected cross-site scripting in /api/icon/getDynamicIcon due to unsanitized SVG input. The endpoint generates SVG images for text icons (type=8). The content query parameter is inserted directly into the SVG <text> tag without XML escaping. Since the response Content-Type is image/svg+xml, injecting unescaped tags allows breaking the XML structure and executing JavaScript. Version 3.5.4 patches the issue.]
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (21.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 21st percentile — 21.1% 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: 0.003 · change: +0.000
Affected products
- B3log Siyuan
- Siyuan-Note Siyuan — versions < 3.5.4
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-w836-5gpm-7r93 (Exploit, Patch, Vendor Advisory)
- github.com/siyuan-note/siyuan/issues/16844 (Patch, Issue Tracking)
- github.com/siyuan-note/siyuan/commit/5c0cc375b47567e15edd2119066b09bb0aa18777 (Patch)
Frequently asked questions
- What is CVE-2026-23847?
- CVE-2026-23847 is a medium-severity vulnerability in B3log Siyuan, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-01-19.
- How severe is CVE-2026-23847?
- Medium severity. CVSS v3 base score is 6.1 out of 10.