CVE-2026-39991: QNAP Systems Inc Notes Station 3

Medium severity, CVSS 4.8. EPSS: 0.3% chance of exploitation in the next 30 days.

A cross-site scripting (XSS) vulnerability has been reported to affect Notes Station 3. If a remote attacker gains a user account, they can then exploit the vulnerability to inject malicious code. We have already fixed the vulnerability in the following version: Notes Station 3 3.9.12 and later

Affected products

• QNAP Systems Inc Notes Station 3: from 3.9, before 3.9.12 (fixed in 3.9.12)

Published 2026-10-15. Last modified 2026-10-15.