CVE-2026-34605: b3log Siyuan

Medium severity, CVSS 6.1. EPSS: 0.6% chance of exploitation in the next 30 days.

SiYuan is a personal knowledge management system. From version 3.6.0 to before version 3.6.2, the SanitizeSVG function introduced in version 3.6.0 to fix XSS in the unauthenticated /api/icon/getDynamicIcon endpoint can be bypassed by using namespace-prefixed element names such as <x:script xmlns:x="http://www.w3.org/2000/svg">. The Go HTML5 parser records the element's tag as "x:script" rather than "script", so the tag check passes it through. The SVG is served with Content-Type: image/svg+xml and no Content Security Policy; when a browser opens the response directly, its XML parser resolves the prefix to the SVG namespace and executes the embedded script. This issue has been patched in version 3.6.2.

Affected products

• b3log Siyuan: from 3.6.0, before 3.6.2 (fixed in 3.6.2)

Published 2026-03-31. Last modified 2026-06-17.