CVE-2026-31807 — SiYuan has a SVG Sanitizer Bypass via `<animate>` Element — Unauthenticated XSS

Description (CNA)

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 (CNA)

Vendor / product	Versions
siyuan-note / siyuan	affected < 3.5.10

CWE

CWE-79

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-5hc8-qmg8-pw27

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.