CVE-2026-32940
CRITICAL
GHSA-4mx9-3c2h-hwhg
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
Lifecycle Timeline
2Tags
Description
SiYuan is a personal knowledge management system. In versions 3.6.0 and below, SanitizeSVG has an incomplete blocklist - it blocks data:text/html and data:image/svg+xml in href attributes but misses data:text/xml and data:application/xml, both of which can render SVG with JavaScript execution. The unauthenticated /api/icon/getDynamicIcon endpoint serves user-controlled input (via the content parameter) directly into SVG markup using fmt.Sprintf with no escaping, served as Content-Type: image/svg+xml. This creates a click-through XSS: a victim navigates to a crafted URL, sees an SVG with an injected link, and clicking it triggers JavaScript via the bypassed MIME types. The attack requires direct navigation to the endpoint or <object>/<embed> embedding, since <img> tag rendering in the frontend doesn't allow interactive links. This issue has been fixed in version 3.6.1.
Analysis
SiYuan personal knowledge management system contains a cross-site scripting (XSS) vulnerability in versions 3.6.0 and below. An unauthenticated attacker can exploit the /api/icon/getDynamicIcon endpoint by crafting a malicious URL that bypasses SVG sanitization filters, allowing arbitrary JavaScript execution when a victim clicks an injected link within the rendered SVG. …
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Remediation
Within 24 hours: Disable the /api/icon/getDynamicIcon endpoint at the network perimeter or WAF level; notify all SiYuan users to avoid clicking untrusted links within the application. Within 7 days: Implement network segmentation to limit SiYuan access to trusted internal networks only; deploy content security policy (CSP) headers to restrict script execution; evaluate alternative knowledge management systems without this vulnerability. …
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