Vulnerability Description
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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-99rq-75j6-5j9f
- https://www.vulncheck.com/advisories/siyuan-before-stored-and-reflected-xss-via-
- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-99rq-75j6-5j9f
FAQ
What is CVE-2026-66394?
CVE-2026-66394 is a vulnerability with a CVSS score of 8.7 (HIGH). 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 cl...
How severe is CVE-2026-66394?
CVE-2026-66394 has been rated HIGH with a CVSS base score of 8.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-66394?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.