CVE-2025-66277: QNAP QTS

Critical severity, CVSS 9.8. EPSS: 0.7% chance of exploitation in the next 30 days.

A link following vulnerability has been reported to affect several QNAP operating system versions. The remote attackers can then exploit the vulnerability to traverse the file system to unintended locations. We have already fixed the vulnerability in the following versions: QTS 5.2.8.3350 build 20251216 and later QuTS hero h5.3.2.3354 build 20251225 and later QuTS hero h5.2.8.3350 build 20251216 and later

Affected products

• QNAP QTS: version 5.2.0.2737 only; version 5.2.0.2744 only; version 5.2.0.2782 only; version 5.2.0.2802 only; version 5.2.0.2823 only; version 5.2.0.2851 only; …
• QNAP Quts Hero: version h5.2.0.2737 only; version h5.2.0.2782 only; version h5.2.0.2789 only; version h5.2.0.2802 only; version h5.2.0.2823 only; version h5.2.0.2851 only; …

Published 2026-02-11. Last modified 2026-06-17.