CVE-2026-77086: Siyuan-Note Siyuan

Critical severity, CVSS 9.1. EPSS: 1% chance of exploitation in the next 30 days.

SiYuan before v3.7.4 fails to validate the packageName parameter in Bazaar install and uninstall endpoints, allowing authenticated administrators to perform path traversal via directory traversal sequences. Attackers with admin access can write arbitrary files to any location via install operations or recursively delete directories via uninstall operations by supplying crafted packageName values.

Affected products

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

Published 2026-08-21. Last modified 2026-08-26.