No exploitation reportedFix available

CVE-2021-34345

Q: Is CVE-2021-34345 actively exploited?

Active exploitation of CVE-2021-34345 has not been confirmed. Its EPSS score was 1.6% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-34345?

CVE-2021-34345 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2021-09-10
Fixed in1.0.6
WeaknessCWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A stack buffer overflow vulnerability has been reported to affect QNAP device running NVR Storage Expansion. If exploited, this vulnerability allows attackers to execute arbitrary code. We have already fixed this vulnerability in the following versions of NVR Storage Expansion: NVR Storage Expansion 1.0.6 ( 2021/08/03 ) and later

Timeline

dates in UTC

2021-09-1004:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-34345?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-34345?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Qnap ej1600 firmwareversion to verify

Branch	Affected	Fixed in	Source
1.0	< 1.0.6	1.0.6	NVD

Qnap tl-d1600s firmwareversion to verify

Branch	Affected	Fixed in	Source
1.0	< 1.0.6	1.0.6	NVD

Qnap tl-d400s firmwareversion to verify

Branch	Affected	Fixed in	Source
1.0	< 1.0.6	1.0.6	NVD

11 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Qnap ej1600 firmware to 1.0.6

Advisories and patches

www.qnap.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CNACVSS 3.19.8read 2026-10-23
NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
CNAweakness (CWE)CWE-787read 2026-10-23
NVDweakness (CWE)CWE-787read 2026-10-23
FIRST EPSSEPSS score1.6 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2021-09-10
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-34345?

Is CVE-2021-34345 actively exploited?

Active exploitation of CVE-2021-34345 has not been confirmed. Its EPSS score was 1.6% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-34345?

CVE-2021-34345 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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