SiYuan SVG Sanitizer Bypass

Reflected XSS in SiYuan's /api/icon/getDynamicIcon endpoint allows unauthenticated attackers to inject malicious JavaScript through SVG animation elements that bypass the sanitizer's static filters. The vulnerability exists because the SVG sanitizer blocks script tags and event handlers but fails to restrict <animate> and <set> elements, which can dynamically modify attributes at runtime to execute code. Public exploit code exists and patches are not yet available for affected versions prior to 3.5.10.

SiYuan's SVG sanitizer fails to properly filter malicious href attributes when whitespace characters are inserted into javascript: URLs, allowing reflected cross-site scripting on the unauthenticated /api/icon/getDynamicIcon endpoint. Public exploit code exists for this vulnerability, which bypasses the previous fix for CVE-2026-29183. Attackers can inject executable JavaScript to target unauthenticated users of SiYuan versions prior to 3.5.10.