Stored Cross-Site Scripting Vulnerability in SiYuan by SiYuan Note
CVE-2026-74800

9.4CRITICAL

Key Information:

Vendor

Siyuan-note

Status
Siyuan
Vendor
CVE Published:
17 August 2026

What is CVE-2026-74800?

SiYuan versions prior to v3.7.4 are vulnerable to a stored cross-site scripting flaw due to improper handling of Content-Disposition and X-Content-Type-Options headers when serving arbitrary file assets. This allows authenticated attackers to upload malicious HTML files as assets. When the workspace owner accesses the link to these assets, the scripts can be executed with full kernel API access, posing a significant security risk.

Affected Version(s)

siyuan 0 < 3.7.4

siyuan 3.7.4

References

https://github.com/siyuan-note/siyuan/security/advisories...
vendor-advisory
https://www.vulncheck.com/advisories/siyuan-before-stored...
third-party-advisory

CVSS V4

Score:
9.4
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

alham-rizvi
.