What’s Vulnerable › Vulnerabilities
CVE-2026-31807: SiYuan has a SVG Sanitizer Bypass via `<animate>` Element — Unauthenticated XSS
- Severity: medium (CVSS 6.1 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2026-03-10 · updated 2026-06-17
- Weakness: CWE-79
Description
SiYuan is a personal knowledge management system. Prior to 3.5.10, SiYuan's SVG sanitizer (SanitizeSVG) blocks dangerous elements (<script>, <iframe>, <foreignobject>) and removes on* event handlers and javascript: in href attributes. However, it does NOT block SVG animation elements (<animate>, <set>) which can dynamically set attributes to dangerous values at runtime, bypassing the static sanitization. This allows an attacker to inject executable JavaScript into the unauthenticated /api/icon/getDynamicIcon endpoint (type=8), creating a reflected XSS. This is a bypass of the fix for CVE-2026-29183 (fixed in v3.5.9). This vulnerability is fixed in v3.5.10.
Affected products
- siyuan-note siyuan: before 3.5.10 — fixed in 3.5.10
How to fix
Upgrade to a fixed version: siyuan-note siyuan 3.5.10. Check the vendor advisory for mitigations.
References
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