Relative Path Traversal Vulnerability in QTS and QuTS hero

published 2021-05-21 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-15454

cvss: 8.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.9%; EPSS 0.9% chance of exploitation in 30 days, percentile 61%
public exploits: 0; none known

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.

Patch / fix

fixed in 2

QNAP Systems Inc. QTS 4.3.3.1624 Build 20210416, 4.3.6.1663 Build 20210504, 4.5.2.1630 Build 20210406, 4.5.3
QNAP Systems Inc. QuTS hero h4.5.2.1638 Build 20210414

Exploit prediction

0.94% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:P/A:N

Affected products

QNAP Systems Inc. QTS
QNAP Systems Inc. QuTS hero

Classification

Weakness

CWE-284 Improper Access Control
CWE-23 Relative Path Traversal
CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

qnap.com /zh-tw/security-advisory/qsa-21-14
vendor-advisory

Sources

CVE List CVE-2021-28798
NVD CVE-2021-28798

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Summary