What is CVE-2026-66396?

CVE-2026-66396 is a high-severity vulnerability in Siyuan-note Siyuan, classified under Cross-site Scripting. CVSS score: 8.4/10. Published 2026-07-27.

How severe is CVE-2026-66396?

High severity. CVSS v3 base score is 8.4 out of 10.

XSS in Siyuan-note Siyuan

CVE-2026-66396

SiYuan before v3.7.2 fails to escape the title-img Individual Attribute List value when rendering Gallery and Kanban cover images, allowing stored cross-site scripting via unescaped style attribute interpolation. Attackers with editor perm…

Vulnerability class: XSS (Cross-Site Scripting)

CVSS v3 metric

CVSS v3 base score 8.4 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H.

Affected products

Siyuan-note Siyuan — versions 0, 3.7.2

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

disclosure@vulncheck.com (vendor-advisory)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-66396?: CVE-2026-66396 is a high-severity vulnerability in Siyuan-note Siyuan, classified under Cross-site Scripting. CVSS score: 8.4/10. Published 2026-07-27.
How severe is CVE-2026-66396?: High severity. CVSS v3 base score is 8.4 out of 10.