Is CVE-2021-34343 in the CISA KEV catalog?

No. CVE-2021-34343 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-34343?

CVE-2021-34343 has a CVSS v3 base score of 6.0 (MEDIUM).

What is the EPSS score for CVE-2021-34343?

CVE-2021-34343 has an EPSS score of 1.95% (78th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-34343?

Upgrade qts to 5.0.0.1716 or later. Fixes are available for 3 affected products.

CVE & CISA-KEV Catalog

CVE-2021-34343

MEDIUMEPSS 78th pctl

6.0

CVSS v3

NVD

Description

A stack buffer overflow vulnerability has been reported to affect QNAP device running QTS, QuTScloud, QuTS hero. If exploited, this vulnerability allows attackers to execute arbitrary code. We have already fixed this vulnerability in the following versions of QTS, QuTScloud, QuTS hero: QTS 4.5.4.1715 build 20210630 and later QTS 5.0.0.1716 build 20210701 and later QuTScloud c4.5.6.1755 and later QuTS hero h4.5.4.1771 build 20210825 and later

CWE-787Out-of-bounds Write

How to fix

Remediation Available

qtsNVD

Affected:>= 5.0.0, < 5.0.0.1716Fixed in:5.0.0.1716CVE-2021-34343derived from NVD

quts heroNVD

Affected:< h4.5.4.1771Fixed in:h4.5.4.1771CVE-2021-34343derived from NVD

qutscloudNVD

Affected:< c4.5.6.1755Fixed in:c4.5.6.1755CVE-2021-34343derived 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 RequiredHigh

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityHigh

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

Exploit Intelligence

1.95%probability of exploitation in 30 days

78thpercentile

Elevated risk: more likely to be exploited than 78% of all known CVEs.

References

Vendor Advisory1

qnap.com

Related Vulnerabilities

Other CWE-787 (Out-of-bounds Write) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-22457	Critical	9.0	100%	KEV + Ransom	Fix
CVE-2025-0282	Critical	9.0	100%	KEV + Ransom	-
CVE-2015-3113	Critical	9.8	100%	KEV	Fix
CVE-2021-20038	Critical	9.8	100%	KEV + Ransom	-
CVE-2023-4863	High	8.8	100%	KEV	Fix
CVE-2020-16040	Medium	6.5	100%	-	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.