by Kastro
Paper/Archive/CVE-2026-66394

CVE-2026-66394

siyuan-note siyuan — SiYuan before v3.7.3 Stored and Reflected XSS via SVG Sanitizer Bypass

EPSS 0.3%public exploitCVSS 9.3
critical.is priorityof 100
43
CVSS 9.3 (CNA)9.3 / 10 × 3027.9Not in CISA KEV+300.0EPSS percentile 27.0.270 × 205.4Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
siyuan< 3.7.33.7.3CNA

Scores by source

VulnCheck (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
VulnCheck (CNA)8.7CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
CISA ADPSSVCExploitation: poc · Automatable: no · Technical impact: partial

References

exploitgithub.com/siyuan-note/siyuan/security/advisories/GHSA-99rq-75j6-5j9fwriteupvulncheck.com/advisories/siyuan-before-stored-and-reflected-xss-via-svg-sanitizer-bypass