CVE-2026-66396

critical

Description

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 permissions can inject onload handlers that execute arbitrary code in the Electron renderer with full Node.js access when victims open affected documents.

References

https://www.vulncheck.com/advisories/siyuan-before-stored-xss-to-rce-via-title-img-ial

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-5rxg-wh59-mg34

Details

Source: Mitre, NVD

Published: 2026-07-27

Updated: 2026-07-28

Risk Information

CVSS v2

Base Score: 8.3

Vector: CVSS2#AV:N/AC:L/Au:M/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 8.4

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H

Severity: High

CVSS v4

Base Score: 9.3

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Severity: Critical

EPSS

EPSS: 0.00296