CVE-2026-74903: Siyuan-Note Siyuan

Medium severity, CVSS 4.3. EPSS: 0.3% chance of exploitation in the next 30 days.

SiYuan before v3.7.4 contains an insufficient access control vulnerability in the /api/lute/spinBlockDOM endpoint, which is guarded only by CheckAuth middleware instead of CheckAdminRole like its sibling endpoint. Authenticated users with RoleEditor or RoleReader roles can invoke the endpoint to transform arbitrary DOM input, and large payloads cause endpoint starvation through per-path mutex serialization.

Affected products

• Siyuan-Note Siyuan: before 3.7.4 (fixed in 3.7.4)

Published 2026-08-18. Last modified 2026-08-26.