CVE-2021-34343
Buffer Overflow Vulnerability in QTS, QuTS hero, and QuTScloud
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
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Buffer Overflow Vulnerability in QTS, QuTS hero, and QuTScloud
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
- Record
CVE-2021-34343- CVSS 3.1
- 6.0 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:H - Weakness
- CWE-787
- Updated
- 2026-11-02
EUVDEUVD-2021-21003
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
- Record
EUVD-2021-21003- CVSS 3.1
- 6.0 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-h5w8-c4g8-8ch6No score
A stack buffer overflow vulnerability has been reported to affect QNAP device running QTS,...
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
- Record
GHSA-h5w8-c4g8-8ch6- Weakness
- CWE-120, CWE-787
- Updated
- 2026-11-02
NVD
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
- Record
CVE-2021-34343- CVSS 3.1
- 6.0 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:H - CVSS 3.1
- 7.2 High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:P - Weakness
- CWE-787
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-34343 is a medium vulnerability (CVSS 6.0) in Qnap Qts, published September 10, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.95%, the 80th percentile. No source names a fixed version.