PT-2026-64995 · Siyuan Note · Siyuan

Joyghoshs · CVE-2026-66394 · Published 2026-07-27 · Updated 2026-07-27

Mitre

CVSS v3.1

8.7

High

Base vector

AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

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.

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2026-66394

Affected Products

Siyuan

References · 3

• 🔥 https://github.com/siyuan-note/siyuan/security/advisories/GHSA-99rq-75j6-5j9f · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-66394 · Security Note
• https://vulncheck.com/advisories/siyuan-before-stored-and-reflected-xss-via-svg-sanitizer-bypass · Note