CVE-2026-74800

CRITICAL 9.0

SiYuan before v3.7.4 Stored XSS via assets endpoint

CVSS Score

9.0

EPSS Score

0.0%

EPSS Percentile

0th

SiYuan before v3.7.4 fails to set Content-Disposition and X-Content-Type-Options headers when serving arbitrary file assets, allowing stored cross-site scripting attacks. Authenticated attackers can upload HTML files as assets and execute scripts with full kernel API access when the workspace owner opens the asset link.

CWE	CWE-79
Vendor	siyuan-note
Product	siyuan
Published	Aug 17, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

siyuan-note / siyuan

0 < 3.7.4

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/siyuan-note/siyuan/security/advisories/GHSA-mjf3-jwmf-r6wf vulncheck.com: https://www.vulncheck.com/advisories/siyuan-before-stored-xss-via-assets-endpoint

Credits

🔍 alham-rizvi