High severity · published Sep 18, 2026
CVE-2026-93923
SiYuan through 3.8.4 Stored XSS via Heading Style Attribute
8.8
CVSS
0.6%
EPSS
No
On KEV
Description
SiYuan through 3.8.4 fails to escape heading style attributes when rendering outline and bookmark dock HTML, allowing stored cross-site scripting. Attackers can supply crafted notebooks or call administrative endpoints to inject malicious style values that execute in the Electron renderer with full system access.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 48% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SI
siyuan · siyuan-note
through 3.8.4 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-93923
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-93923
github.com
https://github.com/siyuan-note/siyuan
github.com
https://github.com/siyuan-note/siyuan/blob/v3.8.4/app/src/util/Tree.ts#L133
github.com
https://github.com/siyuan-note/siyuan/blob/v3.8.4/app/src/util/Tree.ts#L194
github.com
https://github.com/siyuan-note/siyuan/blob/v3.8.4/kernel/model/render.go#L71-L76
github.com
https://github.com/siyuan-note/siyuan/security/advisories/GHSA-928g-4hfq-qwvx
www.vulncheck.com
https://www.vulncheck.com/advisories/siyuan-through-3.8.4-stored-xss-via-heading-style-attribute
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