CVE-2021-28798: QNAP QTS

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

A relative path traversal vulnerability has been reported to affect QNAP NAS running QTS and QuTS hero. If exploited, this vulnerability allows attackers to modify files that impact system integrity. QNAP have already fixed this vulnerability in the following versions: QTS 4.5.2.1630 Build 20210406 and later QTS 4.3.6.1663 Build 20210504 and later QTS 4.3.3.1624 Build 20210416 and later QuTS hero h4.5.2.1638 Build 20210414 and later QNAP NAS running QTS 4.5.3 are not affected.

Affected products

• QNAP QTS: from 4.3.2.0144, before 4.3.3.1624 (fixed in 4.3.3.1624); from 4.3.4.0000, before 4.3.6.1663 (fixed in 4.3.6.1663); from 4.4.0000, before 4.5.2.1630 (fixed in 4.5.2.1630)
• QNAP Quts Hero: before h4.5.2.1638 (fixed in h4.5.2.1638)

Published 2021-05-21. Last modified 2026-06-17.