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CVE-2026-66394

SiYuan before v3.7.3 Stored and Reflected XSS via SVG Sanitizer Bypass

Published: Jul 27, 2026Updated: Jul 28, 2026 Sources: CVE List NVDCWE-79
8.7HIGH
NVD MITRE
EPSS Score
0.3%
Top 81.5%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Not available

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:RS:CC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:RUser Interaction
Required
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-79

Affected Products

siyuan-note
commercial
siyuanOn-premDesktop App
Consumer Software / productivity

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-99rq-75j6-5j9f
github.com
https://www.vulncheck.com/advisories/siyuan-before-stored-and-reflected-xss-via-svg-sanitizer-bypass
vulncheck.com

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