Is CVE-2021-28798 in the CISA KEV catalog?

No. CVE-2021-28798 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-28798?

CVE-2021-28798 has a CVSS v3 base score of 8.8 (HIGH).

What is the EPSS score for CVE-2021-28798?

CVE-2021-28798 has an EPSS score of 0.94% (57th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-28798?

Upgrade qts to 4.5.2.1630 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2021-28798

HIGH

8.8

CVSS v3

NVD

Description

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.

CWE-23 CWE-284Improper Access Control CWE-22Path Traversal

How to fix

Remediation Available

qtsNVD

Affected:>= 4.4.0000, < 4.5.2.1630Fixed in:4.5.2.1630CVE-2021-28798derived from NVD

quts heroNVD

Affected:< h4.5.2.1638Fixed in:h4.5.2.1638CVE-2021-28798derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.94%probability of exploitation in 30 days

57thpercentile

Moderate risk: more likely to be exploited than 57% of all known CVEs.

References

Vendor Advisory1

qnap.com

Related Vulnerabilities

Other CWE-23 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-27199	High	7.3	100%	KEV + Ransom	Fix
CVE-2020-5410	High	7.5	96%	KEV	Fix
CVE-2021-40870	Critical	9.8	92%	KEV	Fix
CVE-2025-64446	Critical	9.8	89%	KEV	Fix
CVE-2020-5405	Medium	6.5	69%	-	Fix
CVE-2025-55752	High	7.5	67%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.