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Fencer Intel
medium 6.0

CVE-2021-34343 json

Buffer Overflow Vulnerability in QTS, QuTS hero, and QuTScloud

published 5y ago modified 4mo ago also EUVD-2021-21003

cvss
6.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

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

Patch / fix

  • QNAP Systems Inc. QTS 4.5.4.1715 build 20210630, 5.0.0.1716 build 20210701
  • QNAP Systems Inc. QuTScloud c4.5.6.1755
  • QNAP Systems Inc. QuTS hero h4.5.4.1771 build 20210825

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Exploit prediction

1.95% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.0 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:H
NVD 3.1 7.2 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P

Affected products

  • QNAP Systems Inc. QTS
  • QNAP Systems Inc. QuTScloud
  • QNAP Systems Inc. QuTS hero

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.