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)
EPSS: 0.003 (18.0th percentile) — read the EPSS interpretation.
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.
Affected products
- B3log Siyuan
- Siyuan-note Siyuan — versions < 3.5.4
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Patch, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Patch, x_refsource_MISC)
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.