CVE-2026-66394: SiYuan before v3.7.3 Stored and Reflected XSS via SVG Sanitizer Bypass
SiYuan before v3.7.3 contains stored and reflected cross-site scripting vulnerabilities in SVG sanitization that allows authenticated attackers to execute scripts by bypassing the HTML parser-based cleaner. Attackers can hide script tags within desc, style, or noscript elements which the HTML parser treats as raw text but browsers interpret as executable SVG content when served as image/svg+xml, enabling script execution in the application origin.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
SiYuanto a version that resolves this vulnerability.Fixed in v3.7.3
Event History
Frequently Asked Questions
What is the severity of CVE-2026-66394?
CVE-2026-66394 has a high severity rating of 8.7.
How do I fix CVE-2026-66394?
To fix CVE-2026-66394, ensure that you upgrade to SiYuan version 3.7.3 or later.
What type of vulnerabilities does CVE-2026-66394 contain?
CVE-2026-66394 contains stored and reflected cross-site scripting (XSS) vulnerabilities.
Who is affected by CVE-2026-66394?
Authenticated attackers are affected by CVE-2026-66394, as they can exploit these vulnerabilities.
What components of SiYuan are impacted by CVE-2026-66394?
CVE-2026-66394 impacts the SVG sanitization process in SiYuan prior to version 3.7.3.