CVE-2026-87809: Siyuan-Note Siyuan

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Siyuan before v3.8.2 fails to apply publish-access filtering to embedded blocks before rendering in the /api/export/preview and /api/lute/copyStdMarkdown endpoints. Attackers with reader access can retrieve the full rendered content of private, hidden, or publish-disabled blocks by accessing public documents containing embed queries that select those blocks.

Affected products

• Siyuan-Note Siyuan: before 3.8.2 (fixed in 3.8.2)

Published 2026-09-09. Last modified 2026-09-18.